diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2cd314dbf1..3557db1a6f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,6 +20,7 @@ on:
       - purescript.cabal
       - Setup.hs
       - stack.yaml
+      - stack.yaml.lock
       - update-changelog.hs
       - weeder.dhall
   release:
@@ -32,7 +33,7 @@ defaults:
 env:
   CI_PRERELEASE: "${{ github.event_name == 'push' && github.ref == 'refs/heads/master' }}"
   CI_RELEASE: "${{ github.event_name == 'release' }}"
-  STACK_VERSION: "2.15.1"
+  STACK_VERSION: "3.3.1"
 
 concurrency:
   # We never want two prereleases building at the same time, since they would
@@ -53,16 +54,18 @@ jobs:
       fail-fast: false # do not cancel builds for other OSes if one fails
       matrix:
         include:
-          - # If upgrading the Haskell image, also upgrade it in the lint job below
-            os: ["ubuntu-latest"]
-            image: haskell:9.2.8@sha256:b3b2f3909c7381bb96b8f18766f9407a3d6f61e0f07ea95e812583ac4f442cbb
-          - os: ["macOS-14"]
-          - os: ["windows-2019"]
-          - os: ["self-hosted", "macos", "ARM64"]
-          - os: ["self-hosted", "Linux", "ARM64"]
+          - image: haskell:9.6.6  # Also upgrade version in the lint job below
+            os: ubuntu-latest  # Exact version is not important, as it's only the container host)
+
+          - image: haskell:9.6.6
+            os: ubuntu-24.04-arm  # Exact version is not important, as it's only the container host
+
+          - os: macos-13  # x64
+          - os: macos-14  # arm64
+          - os: windows-2019  # x64
 
     runs-on: "${{ matrix.os }}"
-    container: "${{ matrix.image }}"
+    container:  "${{ matrix.image }}"
 
     outputs:
       do-not-prerelease: "${{ steps.build.outputs.do-not-prerelease }}"
@@ -71,43 +74,40 @@ jobs:
     steps:
       - # We need `gh` installed on the Linux version. Otherwise, release artifacts won't be uploaded.
         name: "(Linux only) Install gh"
-        if: "contains(matrix.os, 'ubuntu-latest')"
+        if: startsWith(matrix.image, 'haskell')
         run: |
           curl -fsSL https://cli.github.com/packages/githubcli-archive-keyring.gpg | dd of=/usr/share/keyrings/githubcli-archive-keyring.gpg
           chmod go+r /usr/share/keyrings/githubcli-archive-keyring.gpg
           echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/githubcli-archive-keyring.gpg] https://cli.github.com/packages stable main" | tee /etc/apt/sources.list.d/github-cli.list > /dev/null
           apt-get update
-          apt-get install gh
+          apt-get install -y gh
 
-      - uses: "actions/checkout@v2"
-      - uses: "actions/setup-node@v2"
+      - uses: "actions/checkout@v4"
+      - uses: "actions/setup-node@v4"
         with:
-          node-version: "16"
+          node-version: "22"
 
       - id: "haskell"
         name: "(Non-Linux only) Install Haskell"
-        # Note: here we exclude the self-hosted runners because this action does not work on ARM
-        # and their Haskell environment is instead provided by a nix-shell
-        # See https://github.com/purescript/purescript/pulls/4455
-        if: "!contains(matrix.os, 'ubuntu-latest') && !contains(matrix.os, 'self-hosted')"
+        if: startsWith(matrix.os, 'macos') || startsWith(matrix.os, 'windows')
         uses: "haskell-actions/setup@v2"
         with:
+          ghc-version: "9.6.6"
           enable-stack: true
           stack-version: "${{ env.STACK_VERSION }}"
           stack-no-global: true
 
-      - name: "(Linux only) Check Stack version and fix working directory ownership"
-        if: "contains(matrix.os, 'ubuntu-latest')"
+      - name: "(Linux only) Fix working directory ownership"
+        if: startsWith(matrix.image, 'haskell')
         run: |
-          [ "$(stack --numeric-version)" = "$STACK_VERSION" ]
           chown root:root .
 
-      - uses: "actions/cache@v2"
+      - uses: "actions/cache@v4"
         with:
           path: |
             /root/.stack
             ${{ steps.haskell.outputs.stack-root }}
-          key: "${{ matrix.image || runner.os }}--MdyPsf-${{ hashFiles('stack.yaml') }}"
+          key: "${{ matrix.image || runner.os }}--MdyPsf-${{ hashFiles('stack.yaml.lock', 'purescript.cabal') }}"
 
       - name: "(Windows only) Configure Stack to store its programs in STACK_ROOT"
         # This ensures that the local GHC and MSYS binaries that Stack installs
@@ -122,16 +122,16 @@ jobs:
         run: "ci/fix-home ci/build.sh"
 
       - name: "(Linux only) Glob tests"
-        if: "contains(matrix.os, 'ubuntu-latest')"
+        if: startsWith(matrix.image, 'haskell')
         working-directory: "sdist-test"
         # We build in this directory in build.sh, so this is where we need to
         # launch `stack exec`. The actual glob checks happen in a temporary directory.
         run: |
-          apt-get install tree
+          apt-get install -y tree
           ../ci/fix-home stack exec bash ../glob-test.sh
 
       - name: "(Linux only) Build the entire package set"
-        if: "contains(matrix.os, 'ubuntu-latest')"
+        if: startsWith(matrix.image, 'haskell')
         # We build in this directory in build.sh, so this is where we need to
         # launch `stack exec`. The actual package-set building happens in a
         # temporary directory.
@@ -144,11 +144,11 @@ jobs:
         # Moreover, npm has a hook issue that will cause spago to fail to install
         # We upgrade npm to fix this
         run: |
-          npm i -g npm@8.8.0
+          apt-get install -y jq
           ../ci/fix-home stack --haddock exec ../ci/build-package-set.sh
 
       - name: Verify that 'libtinfo' isn't in binary
-        if: "runner.os == 'Linux'"
+        if: runner.os == 'Linux'
         working-directory: "sdist-test"
         run: |
           if [ $(ldd $(../ci/fix-home stack path --local-doc-root)/../bin/purs | grep 'libtinfo' | wc -l) -ge 1 ]; then
@@ -157,17 +157,6 @@ jobs:
             exit 1
           fi
 
-      - name: "(Self-hosted Linux ARM64 only) Patch the binary to work on non-Nix systems"
-        if: "runner.os == 'Linux' && runner.arch == 'ARM64'"
-        working-directory: "sdist-test"
-        # The self-hosted build happens inside a nix-shell that provides a working stack binary
-        # on ARM systems, and while the macOS binary is fine - because macOS binaries are almost
-        # statically linked), the linux ones are all pointing at the nix store.
-        # So here we first point the binary to the right linker that should work on a generic linux,
-        # and then fix the RUNPATH with the right location to load the shared libraries from
-        run: |
-          patchelf --set-interpreter /usr/lib/ld-linux-aarch64.so.1 --set-rpath /usr/lib/aarch64-linux-gnu $(stack path --local-doc-root)/../bin/purs
-
       - name: "(Release/prerelease only) Create bundle"
         if: "${{ env.CI_RELEASE == 'true' || env.CI_PRERELEASE == 'true' && steps.build.outputs.do-not-prerelease != 'true' }}"
         run: |
@@ -199,7 +188,7 @@ jobs:
 
       - name: "(Prerelease only) Upload bundle"
         if: "${{ env.CI_PRERELEASE == 'true' && steps.build.outputs.do-not-prerelease != 'true' }}"
-        uses: "actions/upload-artifact@v3"
+        uses: "actions/upload-artifact@v4.6.0"
         with:
           name: "${{ runner.os }}-${{ runner.arch }}-bundle"
           path: |
@@ -208,59 +197,39 @@ jobs:
 
       - name: "(Release only) Publish bundle"
         if: "${{ env.CI_RELEASE == 'true' }}"
-        # This requires the gh command line tool to be installed on our
-        # self-hosted runners
         env:
           GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
         run: "gh release upload --clobber ${{ github.ref_name }} sdist-test/bundle/*.{tar.gz,sha}"
 
   lint:
-    runs-on: "ubuntu-latest"
-    # At the moment, this is a different image from the image used for
-    # compilation, though the GHC versions match. This is because the
-    # compilation image uses an old version of glibc, which we want because it
-    # means our published binaries will work on the widest number of platforms.
-    # But the HLint binary downloaded by this job requires a newer glibc
-    # version.
-    container: haskell:9.2.8@sha256:b3b2f3909c7381bb96b8f18766f9407a3d6f61e0f07ea95e812583ac4f442cbb
+    container: haskell:9.6.6
+    runs-on: ubuntu-latest  # Exact version is not important, as it's only the container host
 
     steps:
-      - uses: "actions/checkout@v2"
+      - uses: "actions/checkout@v4"
 
       - name: "Fix working directory ownership"
         run: |
           chown root:root .
 
-      - uses: "actions/cache@v2"
+      - uses: "actions/cache@v4"
         with:
           path: |
             /root/.stack
-          key: "lint-${{ hashFiles('stack.yaml') }}"
+          key: "lint-${{ hashFiles('stack.yaml.lock', 'purescript.cabal') }}"
 
       - run: "ci/fix-home ci/run-hlint.sh --git"
         env:
           VERSION: "3.5"
 
-      # Note: the weeder version will need to be updated when we next update our version
-      # of GHC.
-      #
-      # weeder-2.2.0 has somewhat strange version deps. It doesn't appear to
-      # support the exact versions of dhall and generic-lens in LTS-18.
-      # However, forcing it to use the versions of dhall and generic-lens in
-      # LTS-18 doesn't cause any problems when building, so the following
-      # commands build weeder while ignoring version constraints.
       - name: Install weeder
         run: |
-          # The `stack.yaml` file is copied to a separate file so that
-          # adding `allow-newer: true` doesn't affect any subsequant
-          # calls to `stack`.
-          cp stack.yaml stack-weeder.yaml
-          # `allow-newer: true` is needed so that weeder-2.2.0 can be
-          # installed with the dependencies present in LTS-18.
-          echo 'allow-newer: true' >> stack-weeder.yaml
-          ci/fix-home stack --no-terminal --jobs=2 build --copy-compiler-tool --stack-yaml ./stack-weeder.yaml weeder-2.4.0
+          ci/fix-home stack --no-terminal --jobs=2 \
+            build --copy-compiler-tool weeder-2.8.0
 
-      - run: "ci/fix-home stack --no-terminal --jobs=2 build --fast --ghc-options -fwrite-ide-info"
+      - run: |
+          ci/fix-home stack --no-terminal --jobs=2 \
+            build --fast --ghc-options -fwrite-ide-info
 
       - run: "ci/fix-home stack exec weeder"
 
@@ -268,26 +237,28 @@ jobs:
       # reference from our test suite to count in the above check; the fact
       # that a function is tested is not evidence that it's needed. But we also
       # don't want to leave weeds lying around in our test suite either.
-      - run: "ci/fix-home stack --no-terminal --jobs=2 build --fast --test --no-run-tests --ghc-options -fwrite-ide-info"
+      - run: |
+          ci/fix-home stack --no-terminal --jobs=2 \
+            build --fast --test --no-run-tests --ghc-options -fwrite-ide-info
 
       - run: "ci/fix-home stack exec weeder"
 
   make-prerelease:
-    runs-on: "ubuntu-latest"
+    runs-on: ubuntu-latest
     needs:
       - "build"
       - "lint"
     if: "${{ github.event_name == 'push' && needs.build.outputs.do-not-prerelease != 'true' }}"
     steps:
-      - uses: "actions/download-artifact@v3"
+      - uses: "actions/download-artifact@v4"
       - uses: "ncipollo/release-action@v1.10.0"
         with:
           tag: "v${{ needs.build.outputs.version }}"
           artifacts: "*-bundle/*"
           prerelease: true
           body: "This is an automated preview release. Get the latest stable release [here](https://github.com/purescript/purescript/releases/latest)."
-      - uses: "actions/checkout@v3"
-      - uses: "actions/setup-node@v3"
+      - uses: "actions/checkout@v4"
+      - uses: "actions/setup-node@v4"
         with:
           node-version: "16.x"
           registry-url: "https://registry.npmjs.org"
diff --git a/.gitignore b/.gitignore
index 0454beffcb..73b2b4678f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,7 +3,6 @@ bin
 dist
 cabal-dev
 .cabal-sandbox
-stack.yaml.lock
 cabal.sandbox.config
 dist-newstyle/
 cabal.project.local*
diff --git a/CHANGELOG.d/internal_upgrade_to_ghc_9.6.md b/CHANGELOG.d/internal_upgrade_to_ghc_9.6.md
new file mode 100644
index 0000000000..6622b6baed
--- /dev/null
+++ b/CHANGELOG.d/internal_upgrade_to_ghc_9.6.md
@@ -0,0 +1,2 @@
+* Upgrade GHC to [`9.6.6`](https://downloads.haskell.org/~ghc/9.6.6/docs/users_guide/9.6.6-notes.html), Stackage LTS `22.43`
+* Minimum required glibc version is bumped from [`2.28` to `2.31`](https://sourceware.org/glibc/wiki/Glibc%20Timeline)
diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index aa5ddefd3f..cfbb98e362 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -16,6 +16,7 @@ If you would prefer to use different terms, please use the section below instead
 | :------- | :--- | :------ |
 | [@5outh](https://github.com/5outh) | Benjamin Kovach | [MIT license] |
 | [@actionshrimp](https://github.com/actionshrimp) | David Aitken | [MIT license] |
+| [@ad-si](https://github.com/ad-si) | Adrian Sieber | [MIT license] |
 | [@adnelson](https://github.com/adnelson) | Allen Nelson | [MIT license] |
 | [@alexbiehl](https://github.com/alexbiehl) | Alexander Biehl | [MIT license] |
 | [@andreypopp](https://github.com/andreypopp) | Andrey Popp | [MIT license] |
diff --git a/INSTALL.md b/INSTALL.md
index 0bccc516c7..03f7748636 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -4,12 +4,13 @@ If you are having difficulty installing the PureScript compiler, feel free to as
 
 ## Requirements
 
-The PureScript compiler is built using GHC 9.2.8, and should be able to run on any operating system supported by GHC 9.2.8. In particular:
+The PureScript compiler is built using GHC 9.6.6, and should be able to run on any operating system supported by GHC 9.6.6.
+In particular:
 
 * for Windows users, versions predating Vista are not officially supported,
 * for macOS / OS X users, versions predating Mac OS X 10.7 (Lion) are not officially supported.
 
-See also <https://www.haskell.org/ghc/download_ghc_9_2_8.html> for more details about the operating systems which GHC 9.2.8 supports.
+See also <https://www.haskell.org/ghc/download_ghc_9_6_6.html> for more details about the operating systems which GHC 9.6.6 supports.
 
 ## Official prebuilt binaries
 
diff --git a/LICENSE b/LICENSE
index 490ff3651c..713d3371a3 100644
--- a/LICENSE
+++ b/LICENSE
@@ -107,7 +107,6 @@ PureScript uses the following Haskell library packages. Their license files foll
   optparse-applicative
   parallel
   parsec
-  pattern-arrows
   pretty
   primitive
   process
@@ -3186,29 +3185,6 @@ parsec LICENSE file:
   negligence or otherwise) arising in any way out of the use of this software,
   even if advised of the possibility of such damage.
 
-pattern-arrows LICENSE file:
-
-  The MIT License (MIT)
-
-  Copyright (c) 2013 Phil Freeman
-
-  Permission is hereby granted, free of charge, to any person obtaining a copy of
-  this software and associated documentation files (the "Software"), to deal in
-  the Software without restriction, including without limitation the rights to
-  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
-  the Software, and to permit persons to whom the Software is furnished to do so,
-  subject to the following conditions:
-
-  The above copyright notice and this permission notice shall be included in all
-  copies or substantial portions of the Software.
-
-  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
-  FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
-  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
-  IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
-  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
 pretty LICENSE file:
 
   This library (libraries/pretty) is derived from code from
diff --git a/Makefile b/Makefile
index 53da1f3710..91235d9c8f 100644
--- a/Makefile
+++ b/Makefile
@@ -4,6 +4,7 @@ package = purescript
 exe_target = purs
 stack_yaml = STACK_YAML="stack.yaml"
 stack = $(stack_yaml) stack
+stack_dir = .stack-work
 
 .DEFAULT_GOAL := help
 
@@ -14,6 +15,10 @@ $(bin_dir)/hlint: ci/install-hlint.sh
 clean: ## Remove build artifacts
 	rm -fr $(bin_dir)
 	rm -fr $(build_dir)
+	rm -fr $(stack_dir)
+	rm -fr dist-newstyle
+	rm -fr .psci_modules
+	rm -fr .test_modules
 
 help: ## Print documentation
 	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
diff --git a/app/Command/Docs.hs b/app/Command/Docs.hs
index 987023c98c..22bd6bdd3f 100644
--- a/app/Command/Docs.hs
+++ b/app/Command/Docs.hs
@@ -15,7 +15,8 @@ import Language.PureScript.Docs qualified as D
 import Language.PureScript.Docs.Tags (dumpCtags, dumpEtags)
 import Language.PureScript.Glob (PSCGlobs(..), toInputGlobs, warnFileTypeNotFound)
 import Options.Applicative qualified as Opts
-import Text.PrettyPrint.ANSI.Leijen qualified as PP
+import Prettyprinter qualified as PP
+import Prettyprinter.Render.Terminal (AnsiStyle)
 import SharedCLI qualified
 import System.Directory (getCurrentDirectory, createDirectoryIfMissing, removeFile)
 import System.Exit (exitFailure)
@@ -113,10 +114,10 @@ defaultOutputForFormat fmt =
     Ctags -> "tags"
 
 pscDocsOptions :: Opts.Parser PSCDocsOptions
-pscDocsOptions = 
-  PSCDocsOptions <$> format 
-                 <*> output 
-                 <*> compileOutputDir 
+pscDocsOptions =
+  PSCDocsOptions <$> format
+                 <*> output
+                 <*> compileOutputDir
                  <*> many SharedCLI.inputFile
                  <*> SharedCLI.globInputFile
                  <*> many SharedCLI.excludeFiles
@@ -150,9 +151,9 @@ infoModList :: Opts.InfoMod a
 infoModList = Opts.fullDesc <> footerInfo where
   footerInfo = Opts.footerDoc $ Just examples
 
-examples :: PP.Doc
+examples :: PP.Doc AnsiStyle
 examples =
-  PP.vcat $ map PP.text
+  PP.vcat
     [ "Examples:"
     , "  write documentation for all modules to ./generated-docs:"
     , "    purs docs \"src/**/*.purs\" \".psc-package/*/*/*/src/**/*.purs\""
diff --git a/app/Command/Ide.hs b/app/Command/Ide.hs
index f5a501af75..38fc9c7e36 100644
--- a/app/Command/Ide.hs
+++ b/app/Command/Ide.hs
@@ -28,7 +28,7 @@ import Data.ByteString.Char8 qualified as BS8
 import Data.ByteString.Lazy.Char8 qualified as BSL8
 import GHC.IO.Exception (IOErrorType(..), IOException(..))
 import Language.PureScript.Ide (handleCommand)
-import Language.PureScript.Ide.Command (Command(..), commandName)
+import Language.PureScript.Ide.Command (commandName, Command(..))
 import Language.PureScript.Ide.Util (decodeT, displayTimeSpec, encodeT, logPerf, runLogger)
 import Language.PureScript.Ide.Error (IdeError(..))
 import Language.PureScript.Ide.State (updateCacheTimestamp)
@@ -199,14 +199,22 @@ startServer port env = Network.withSocketsDo $ do
               logPerf message $ do
                 result <- runExceptT $ do
                   updateCacheTimestamp >>= \case
-                    Nothing -> pure ()
+                    Nothing -> 
+                      handleCommand cmd'
                     Just (before, after) -> do
                       -- If the cache db file was changed outside of the IDE
                       -- we trigger a reset before processing the command
                       $(logInfo) ("cachedb was changed from: " <> show before <> ", to: " <> show after)
-                      unless (isLoadAll cmd') $
-                        void (handleCommand Reset *> handleCommand (LoadSync []))
-                  handleCommand cmd'
+                      let doReload = handleCommand Reset *> handleCommand (LoadSync [])
+                      case cmd' of
+                        -- handleCommand on Load [] already resets the state.
+                        Load [] -> handleCommand cmd'
+                        -- Focus needs to fire before doReload, because we
+                        -- want to set the focused modules first before
+                        -- loading everything with LoadSync [].
+                        Focus _ -> handleCommand cmd' <* doReload
+                        -- Otherwise, just doReload and then handle.
+                        _ -> doReload *> handleCommand cmd'
                 liftIO $ catchGoneHandle $ BSL8.hPutStrLn h $ case result of
                   Right r  -> Aeson.encode r
                   Left err -> Aeson.encode err
@@ -219,11 +227,6 @@ startServer port env = Network.withSocketsDo $ do
                 hFlush stdout
           liftIO $ catchGoneHandle (hClose h)
 
-isLoadAll :: Command -> Bool
-isLoadAll = \case
-  Load [] -> True
-  _ -> False
-
 catchGoneHandle :: IO () -> IO ()
 catchGoneHandle =
   handle (\e -> case e of
diff --git a/app/Main.hs b/app/Main.hs
index c925a4a313..ff4e04ab6d 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -13,9 +13,10 @@ import Command.REPL qualified as REPL
 import Control.Monad (join)
 import Data.Foldable (fold)
 import Options.Applicative qualified as Opts
+import Prettyprinter qualified as Doc
+import Prettyprinter.Render.Terminal (AnsiStyle)
 import System.Environment (getArgs)
 import System.IO qualified as IO
-import Text.PrettyPrint.ANSI.Leijen qualified as Doc
 import Version (versionString)
 
 
@@ -39,11 +40,11 @@ main = do
             "For example, `purs compile --help` displays options specific to the `compile` command."
         , Doc.hardline
         , Doc.hardline
-        , Doc.text $ "purs " ++ versionString
+        , Doc.pretty $ "purs " ++ versionString
         ]
 
-    para :: String -> Doc.Doc
-    para = foldr (Doc.</>) Doc.empty . map Doc.text . words
+    para :: String -> Doc.Doc AnsiStyle
+    para = foldr (\x y -> x <> Doc.softline <> y) mempty . map Doc.pretty . words
 
     -- | Displays full command help when invoked with no arguments.
     execParserPure :: Opts.ParserInfo a -> [String] -> Opts.ParserResult a
diff --git a/cabal.project b/cabal.project
index 51c7ecb87d..61c5c9bd35 100644
--- a/cabal.project
+++ b/cabal.project
@@ -1,2 +1,7 @@
 packages:
   purescript.cabal
+
+source-repository-package
+   type: git
+   location: https://github.com/purescript/cheapskate.git
+   tag: 8bfaf4beeb108e97a274ed51303f278905979e87
diff --git a/ci/build-package-set.sh b/ci/build-package-set.sh
index 12a6fcb34c..f11b556871 100755
--- a/ci/build-package-set.sh
+++ b/ci/build-package-set.sh
@@ -5,7 +5,7 @@ shopt -s nullglob
 
 psroot=$(dirname "$(dirname "$(realpath "$0")")")
 
-if [[ "${CI:-}" && "$(echo $psroot/CHANGELOG.d/breaking_*)" ]]; then
+if [[ "${CI:-}" && "$(echo "$psroot"/CHANGELOG.d/breaking_*)" ]]; then
   echo "Skipping package-set build due to unreleased breaking changes"
   exit 0
 fi
@@ -16,23 +16,17 @@ export PATH="$tmpdir/node_modules/.bin:$PATH"
 cd "$tmpdir"
 
 echo ::group::Ensure Spago is available
-which spago || npm install spago@0.20.8
+which spago || npm install spago@0.93.43
 echo ::endgroup::
 
 echo ::group::Create dummy project
-echo 'let upstream = https://github.com/purescript/package-sets/releases/download/XXX/packages.dhall in upstream' > packages.dhall
-echo '{ name = "my-project", dependencies = [] : List Text, packages = ./packages.dhall, sources = [] : List Text }' > spago.dhall
-spago upgrade-set
-# Override the `metadata` package's version to match `purs` version
-# so that `spago build` actually works
-sed -i'' "\$c in upstream with metadata.version = \"v$(purs --version | { read v z && echo $v; })\"" packages.dhall
-spago install $(spago ls packages | while read name z; do if [[ $name != metadata ]]; then echo $name; fi; done)
+spago init --name purescript-dummy
 echo ::endgroup::
 
 echo ::group::Compile package set
-spago build
+spago ls packages --json | jq -r 'keys[]' | xargs spago install
 echo ::endgroup::
 
 echo ::group::Document package set
-spago docs --no-search
+spago docs
 echo ::endgroup::
diff --git a/purescript.cabal b/purescript.cabal
index 0d32ce4814..93b02ebbc9 100644
--- a/purescript.cabal
+++ b/purescript.cabal
@@ -153,18 +153,17 @@ common defaults
     -- modules must be parseable by this library otherwise the compiler
     -- will reject them. It should therefore always be pinned to a single
     -- specific version.
-    aeson >=2.0.3.0 && <2.1,
-    aeson-better-errors >=0.9.1.1 && <0.10,
-    ansi-terminal >=0.11.3 && <0.12,
+    aeson >=2.0.3.0 && <2.2,
+    aeson-better-errors >=0.9.1.3 && <0.10,
+    ansi-terminal >=0.11.3 && <1.1,
     array >=0.5.4.0 && <0.6,
-    base >=4.16.2.0 && <4.17,
+    base >=4.16.2.0 && <4.19,
     blaze-html >=0.9.1.2 && <0.10,
     bower-json >=1.1.0.0 && <1.2,
     boxes >=0.1.5 && <0.2,
     bytestring >=0.11.3.1 && <0.12,
-    Cabal >=3.6.3.0 && <3.7,
+    Cabal >=3.10.3.0 && <3.11,
     cborg >=0.2.7.0 && <0.3,
-    serialise >=0.2.5.0 && <0.3,
     cheapskate >=0.1.1.2 && <0.2,
     clock >=0.8.3 && <0.9,
     containers >=0.6.5.1 && <0.7,
@@ -177,38 +176,38 @@ common defaults
     file-embed >=0.0.15.0 && <0.1,
     filepath >=1.4.2.2 && <1.5,
     Glob >=0.10.2 && <0.11,
-    haskeline >=0.8.2 && <0.9,
+    haskeline ==0.8.2,
     language-javascript ==0.7.0.0,
-    lens >=5.1.1 && <5.2,
+    lens >=5.1.1 && <5.3,
     lifted-async >=0.10.2.2 && <0.11,
     lifted-base >=0.2.3.12 && <0.3,
-    memory >=0.17.0 && <0.18,
+    memory >=0.17.0 && <0.19,
     monad-control >=1.0.3.1 && <1.1,
     monad-logger >=0.3.36 && <0.4,
     monoidal-containers >=0.6.2.0 && <0.7,
-    mtl >=2.2.2 && <2.3,
+    mtl >=2.2.2 && <2.4,
     parallel >=3.2.2.0 && <3.3,
     parsec >=3.1.15.0 && <3.2,
-    pattern-arrows >=0.0.2 && <0.1,
-    process ==1.6.13.1,
+    process >=1.6.19.0 && <1.7,
     protolude >=0.3.1 && <0.4,
     regex-tdfa >=1.3.1.2 && <1.4,
     safe >=0.3.19 && <0.4,
     scientific >=0.3.7.0 && <0.4,
+    semialign >=1.2.0.1 && <1.4,
     semigroups ==0.20.*,
-    semialign >=1.2.0.1 && <1.3,
+    serialise >=0.2.5.0 && <0.3,
     sourcemap >=0.1.7 && <0.2,
     stm >=2.5.0.2 && <2.6,
     stringsearch >=0.3.6.6 && <0.4,
-    template-haskell >=2.18.0.0 && <2.19,
-    text >=1.2.5.0 && <1.3,
-    these >=1.1.1.1 && <1.2,
-    time >=1.11.1.1 && <1.12,
-    transformers >=0.5.6.2 && <0.6,
+    template-haskell >=2.18.0.0 && <2.21,
+    text >=1.2.5.0 && <2.1,
+    these >=1.1.1.1 && <1.3,
+    time >=1.11.1.1 && <1.13,
+    transformers >=0.5.6.2 && <0.7,
     transformers-base >=0.4.6 && <0.5,
     utf8-string >=1.0.2 && <1.1,
-    vector >=0.12.3.1 && <0.13,
-    witherable >=0.4.2 && <0.5
+    vector >=0.12.3.1 && <0.14,
+    witherable >=0.4.2 && <0.5,
 
 library
   import: defaults
@@ -217,6 +216,7 @@ library
     Control.Monad.Logger
     Control.Monad.Supply
     Control.Monad.Supply.Class
+    Control.PatternArrows
     Language.PureScript
     Language.PureScript.AST
     Language.PureScript.AST.Binders
@@ -403,10 +403,11 @@ executable purs
   main-is: Main.hs
   ghc-options: -fno-warn-unused-do-bind -threaded -rtsopts -with-rtsopts=-N -Wno-unused-packages
   build-depends:
-    ansi-wl-pprint >=0.6.9 && <0.7,
+    prettyprinter >=1.6 && <1.8,
+    prettyprinter-ansi-terminal >=1.1.1 && <1.2,
     exceptions >=0.10.4 && <0.11,
     network >=3.1.2.7 && <3.2,
-    optparse-applicative >=0.17.0.0 && <0.18,
+    optparse-applicative >=0.17.0.0 && <0.19,
     purescript
   if flag(release)
     cpp-options: -DRELEASE
@@ -440,7 +441,7 @@ test-suite tests
   build-depends:
     purescript,
     generic-random >=1.5.0.1 && <1.6,
-    hspec >= 2.10.7 && < 3,
+    hspec >= 2.11.10 && < 3,
     HUnit >=1.6.2.0 && <1.7,
     newtype >=0.2.2.0 && <0.3,
     QuickCheck >=2.14.2 && <2.15,
diff --git a/src/Control/Monad/Supply/Class.hs b/src/Control/Monad/Supply/Class.hs
index e8656f0c69..b10b42d549 100644
--- a/src/Control/Monad/Supply/Class.hs
+++ b/src/Control/Monad/Supply/Class.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE TypeOperators #-}
+
 -- |
 -- A class for monads supporting a supply of fresh names
 --
diff --git a/src/Control/PatternArrows.hs b/src/Control/PatternArrows.hs
new file mode 100644
index 0000000000..b01d1cccdc
--- /dev/null
+++ b/src/Control/PatternArrows.hs
@@ -0,0 +1,118 @@
+-----------------------------------------------------------------------------
+--
+-- Module      :  Control.PatternArrows
+-- Copyright   :  (c) Phil Freeman 2013
+-- License     :  MIT
+--
+-- Maintainer  :  Phil Freeman <paf31@cantab.net>
+-- Stability   :  experimental
+-- Portability :
+--
+-- |
+-- Arrows for Pretty Printing
+--
+-----------------------------------------------------------------------------
+
+{-# LANGUAGE GeneralizedNewtypeDeriving, GADTs #-}
+
+module Control.PatternArrows where
+
+import Prelude
+
+import Control.Arrow ((***), (<+>))
+import Control.Arrow qualified as A
+import Control.Category ((>>>))
+import Control.Category qualified as C
+import Control.Monad.State
+import Control.Monad.Fix (fix)
+
+-- |
+-- A first-order pattern match
+--
+-- A pattern is a Kleisli arrow for the @StateT Maybe@ monad. That is, patterns can fail, and can carry user-defined state.
+--
+newtype Pattern u a b = Pattern { runPattern :: A.Kleisli (StateT u Maybe) a b } deriving (A.Arrow, A.ArrowZero, A.ArrowPlus)
+
+instance C.Category (Pattern u) where
+    id = Pattern C.id
+    Pattern p1 . Pattern p2 = Pattern (p1 C.. p2)
+
+instance Functor (Pattern u a) where
+  fmap f (Pattern p) = Pattern $ A.Kleisli $ fmap f . A.runKleisli p
+
+-- |
+-- Run a pattern with an input and initial user state
+--
+-- Returns Nothing if the pattern fails to match
+--
+pattern_ :: Pattern u a b -> u -> a -> Maybe b
+pattern_ p u = flip evalStateT u . A.runKleisli (runPattern p)
+
+-- |
+-- Construct a pattern from a function
+--
+mkPattern :: (a -> Maybe b) -> Pattern u a b
+mkPattern f = Pattern $ A.Kleisli (lift . f)
+
+-- |
+-- Construct a pattern from a stateful function
+--
+mkPattern' :: (a -> StateT u Maybe b) -> Pattern u a b
+mkPattern' = Pattern . A.Kleisli
+
+-- |
+-- Construct a pattern which recursively matches on the left-hand-side
+--
+chainl :: Pattern u a (a, a) -> (r -> r -> r) -> Pattern u a r -> Pattern u a r
+chainl g f p = fix $ \c -> g >>> ((c <+> p) *** p) >>> A.arr (uncurry f)
+
+-- |
+-- Construct a pattern which recursively matches on the right-hand side
+--
+chainr :: Pattern u a (a, a) -> (r -> r -> r) -> Pattern u a r -> Pattern u a r
+chainr g f p = fix $ \c -> g >>> (p *** (c <+> p)) >>> A.arr (uncurry f)
+
+-- |
+-- Construct a pattern which recursively matches on one-side of a tuple
+--
+wrap :: Pattern u a (s, a) -> (s -> r -> r) -> Pattern u a r -> Pattern u a r
+wrap g f p = fix $ \c -> g >>> (C.id *** (c <+> p)) >>> A.arr (uncurry f)
+
+-- |
+-- Construct a pattern which matches a part of a tuple
+--
+split :: Pattern u a (s, t) -> (s -> t -> r) -> Pattern u a r
+split s f = s >>> A.arr (uncurry f)
+
+-- |
+-- A table of operators
+--
+data OperatorTable u a r = OperatorTable { runOperatorTable :: [ [Operator u a r] ] }
+
+-- |
+-- An operator:
+--
+--  [@AssocL@] A left-associative operator
+--
+--  [@AssocR@] A right-associative operator
+--
+--  [@Wrap@] A prefix-like or postfix-like operator
+--
+--  [@Split@] A prefix-like or postfix-like operator which does not recurse into its operand
+--
+data Operator u a r where
+  AssocL :: Pattern u a (a, a) -> (r -> r -> r) -> Operator u a r
+  AssocR :: Pattern u a (a, a) -> (r -> r -> r) -> Operator u a r
+  Wrap   :: Pattern u a (s, a) -> (s -> r -> r) -> Operator u a r
+  Split  :: Pattern u a (s, t) -> (s -> t -> r) -> Operator u a r
+
+-- |
+-- Build a pretty printer from an operator table and an indecomposable pattern
+--
+buildPrettyPrinter :: OperatorTable u a r -> Pattern u a r -> Pattern u a r
+buildPrettyPrinter table p = foldl (\p' ops -> foldl1 (<+>) (flip map ops $ \case
+    AssocL pat g -> chainl pat g p'
+    AssocR pat g -> chainr pat g p'
+    Wrap pat g -> wrap pat g p'
+    Split pat g -> split pat g
+  ) <+> p') p $ runOperatorTable table
diff --git a/src/Language/PureScript/CodeGen/JS.hs b/src/Language/PureScript/CodeGen/JS.hs
index 14d122a37d..3a4e371187 100644
--- a/src/Language/PureScript/CodeGen/JS.hs
+++ b/src/Language/PureScript/CodeGen/JS.hs
@@ -9,7 +9,6 @@ module Language.PureScript.CodeGen.JS
 import Prelude
 import Protolude (ordNub)
 
-import Control.Applicative (liftA2)
 import Control.Monad (forM, replicateM, void)
 import Control.Monad.Except (MonadError, throwError)
 import Control.Monad.Reader (MonadReader, asks)
diff --git a/src/Language/PureScript/CoreImp/Optimizer/TCO.hs b/src/Language/PureScript/CoreImp/Optimizer/TCO.hs
index 34746ae3db..a1d4a47c2b 100644
--- a/src/Language/PureScript/CoreImp/Optimizer/TCO.hs
+++ b/src/Language/PureScript/CoreImp/Optimizer/TCO.hs
@@ -3,7 +3,7 @@ module Language.PureScript.CoreImp.Optimizer.TCO (tco) where
 
 import Prelude
 
-import Control.Applicative (empty, liftA2)
+import Control.Applicative (empty)
 import Control.Monad (guard)
 import Control.Monad.State (State, evalState, get, modify)
 import Data.Functor (($>), (<&>))
diff --git a/src/Language/PureScript/Docs/RenderedCode/RenderType.hs b/src/Language/PureScript/Docs/RenderedCode/RenderType.hs
index a082b4b833..c6a985b09b 100644
--- a/src/Language/PureScript/Docs/RenderedCode/RenderType.hs
+++ b/src/Language/PureScript/Docs/RenderedCode/RenderType.hs
@@ -233,7 +233,7 @@ renderTypeWithRole = \case
 renderType' :: PrettyPrintType -> RenderedCode
 renderType'
   = fromMaybe (internalError "Incomplete pattern")
-  . PA.pattern matchType ()
+  . PA.pattern_ matchType ()
 
 renderTypeVars :: [(TypeVarVisibility, Text, Maybe PrettyPrintType)] -> RenderedCode
 renderTypeVars tyVars = mintersperse sp (map renderTypeVar tyVars)
@@ -252,4 +252,4 @@ renderTypeAtom = renderTypeAtom' . convertPrettyPrintType maxBound
 renderTypeAtom' :: PrettyPrintType -> RenderedCode
 renderTypeAtom'
   = fromMaybe (internalError "Incomplete pattern")
-  . PA.pattern matchTypeAtom ()
+  . PA.pattern_ matchTypeAtom ()
diff --git a/src/Language/PureScript/Ide.hs b/src/Language/PureScript/Ide.hs
index 57601c3d45..e0ecc4a8f7 100644
--- a/src/Language/PureScript/Ide.hs
+++ b/src/Language/PureScript/Ide.hs
@@ -22,6 +22,7 @@ import Protolude hiding (moduleName)
 
 import "monad-logger" Control.Monad.Logger (MonadLogger, logWarnN)
 import Data.Map qualified as Map
+import Data.Set qualified as Set
 import Data.Text qualified as T
 import Language.PureScript qualified as P
 import Language.PureScript.Glob (toInputGlobs, PSCGlobs(..))
@@ -37,7 +38,7 @@ import Language.PureScript.Ide.Matcher (Matcher)
 import Language.PureScript.Ide.Prim (idePrimDeclarations)
 import Language.PureScript.Ide.Rebuild (rebuildFileAsync, rebuildFileSync)
 import Language.PureScript.Ide.SourceFile (parseModulesFromFiles)
-import Language.PureScript.Ide.State (getAllModules, getLoadedModulenames, insertExterns, insertModule, populateVolatileState, populateVolatileStateSync, resetIdeState)
+import Language.PureScript.Ide.State (getAllModules, getLoadedModulenames, insertExterns, insertModule, populateVolatileState, populateVolatileStateSync, resetIdeState, setFocusedModules, getFocusedModules)
 import Language.PureScript.Ide.Types (Annotation(..), Ide, IdeConfiguration(..), IdeDeclarationAnn(..), IdeEnvironment(..), Success(..))
 import Language.PureScript.Ide.Util (discardAnn, identifierFromIdeDeclaration, namespaceForDeclaration, withEmptyAnn)
 import Language.PureScript.Ide.Usage (findUsages)
@@ -102,6 +103,8 @@ handleCommand c = case c of
     rebuildFileAsync file actualFile targets
   RebuildSync file actualFile targets ->
     rebuildFileSync file actualFile targets
+  Focus modulesToFocus ->
+    setFocusedModules modulesToFocus $> TextResult "Focused modules have been set."
   Cwd ->
     TextResult . T.pack <$> liftIO getCurrentDirectory
   Reset ->
@@ -215,10 +218,18 @@ loadModules
   => [P.ModuleName]
   -> m Success
 loadModules moduleNames = do
+  focusedModules <- getFocusedModules
   -- We resolve all the modulenames to externs files and load these into memory.
   oDir <- outputDirectory
-  let efPaths =
-        map (\mn -> oDir </> toS (P.runModuleName mn) </> P.externsFileName) moduleNames
+  let
+    -- But we only load the externs files that are in the focusedModules.
+    efModules = 
+        if Set.null focusedModules then 
+          moduleNames
+        else 
+          Set.toList $ Set.fromList moduleNames `Set.intersection` focusedModules
+    efPaths =
+        map (\mn -> oDir </> toS (P.runModuleName mn) </> P.externsFileName) efModules
   efiles <- traverse readExternFile efPaths
   traverse_ insertExterns efiles
 
diff --git a/src/Language/PureScript/Ide/Command.hs b/src/Language/PureScript/Ide/Command.hs
index ae4b6c9d8e..49e99a4474 100644
--- a/src/Language/PureScript/Ide/Command.hs
+++ b/src/Language/PureScript/Ide/Command.hs
@@ -62,6 +62,7 @@ data Command
     | List { listType :: ListType }
     | Rebuild FilePath (Maybe FilePath) (Set P.CodegenTarget)
     | RebuildSync FilePath (Maybe FilePath) (Set P.CodegenTarget)
+    | Focus [P.ModuleName]
     | Cwd
     | Reset
     | Quit
@@ -79,6 +80,7 @@ commandName c = case c of
   List{} -> "List"
   Rebuild{} -> "Rebuild"
   RebuildSync{} -> "RebuildSync"
+  Focus{} -> "Focus"
   Cwd{} -> "Cwd"
   Reset{} -> "Reset"
   Quit{} -> "Quit"
@@ -176,6 +178,13 @@ instance FromJSON Command where
           <$> params .: "file"
           <*> params .:? "actualFile"
           <*> (parseCodegenTargets =<< params .:? "codegen" .!= [ "js" ])
+      "focus" -> do
+        params' <- o .:? "params"
+        case params' of
+          Nothing -> 
+            pure (Focus [])
+          Just params ->
+            Focus <$> (map P.moduleNameFromString <$> params .:? "modules" .!= [])
       c -> fail ("Unknown command: " <> show c)
     where
       parseCodegenTargets ts =
diff --git a/src/Language/PureScript/Ide/State.hs b/src/Language/PureScript/Ide/State.hs
index 32478d7000..f11f00ad81 100644
--- a/src/Language/PureScript/Ide/State.hs
+++ b/src/Language/PureScript/Ide/State.hs
@@ -31,6 +31,9 @@ module Language.PureScript.Ide.State
   , populateVolatileStateSTM
   , getOutputDirectory
   , updateCacheTimestamp
+  , getFocusedModules
+  , setFocusedModules
+  , setFocusedModulesSTM
   -- for tests
   , resolveOperatorsForModule
   , resolveInstances
@@ -44,6 +47,7 @@ import Control.Lens (Ixed(..), preview, view, (%~), (.~), (^.))
 import "monad-logger" Control.Monad.Logger (MonadLogger, logWarnN)
 import Data.IORef (readIORef, writeIORef)
 import Data.Map.Lazy qualified as Map
+import Data.Set qualified as Set
 import Data.Time.Clock (UTCTime)
 import Data.Zip (unzip)
 import Language.PureScript qualified as P
@@ -61,7 +65,8 @@ import System.Directory (getModificationTime)
 resetIdeState :: Ide m => m ()
 resetIdeState = do
   ideVar <- ideStateVar <$> ask
-  liftIO (atomically (writeTVar ideVar emptyIdeState))
+  durableState <- getDurableState
+  liftIO (atomically (writeTVar ideVar (emptyIdeState { ideDurableState = durableState })))
 
 getOutputDirectory :: Ide m => m FilePath
 getOutputDirectory = do
@@ -141,6 +146,23 @@ setVolatileStateSTM ref vs = do
     x {ideVolatileState = vs}
   pure ()
 
+-- | Retrieves the DurableState from the State.
+getDurableState :: Ide m => m IdeDurableState
+getDurableState = do
+  st <- ideStateVar <$> ask
+  liftIO (atomically (getDurableStateSTM st))
+
+-- | STM version of getDurableState
+getDurableStateSTM :: TVar IdeState -> STM IdeDurableState
+getDurableStateSTM ref = ideDurableState <$> readTVar ref
+
+-- | Sets the DurableState inside Ide's state
+setDurableStateSTM :: TVar IdeState -> IdeDurableState -> STM ()
+setDurableStateSTM ref md = do
+  modifyTVar ref $ \x ->
+    x {ideDurableState = md}
+  pure ()
+
 -- | Checks if the given ModuleName matches the last rebuild cache and if it
 -- does returns all loaded definitions + the definitions inside the rebuild
 -- cache
@@ -447,3 +469,17 @@ resolveDataConstructorsForModule decls =
       & mapMaybe (preview (idaDeclaration . _IdeDeclDataConstructor))
       & foldr (\(IdeDataConstructor name typeName type') ->
                   Map.insertWith (<>) typeName [(name, type')]) Map.empty
+
+getFocusedModules :: Ide m => m (Set P.ModuleName)
+getFocusedModules = do
+  IdeDurableState{drFocusedModules = focusedModules} <- getDurableState
+  pure focusedModules
+
+setFocusedModules :: Ide m => [P.ModuleName] -> m ()
+setFocusedModules modulesToFocus = do
+  st <- ideStateVar <$> ask
+  liftIO (atomically (setFocusedModulesSTM st modulesToFocus)) 
+
+setFocusedModulesSTM :: TVar IdeState -> [P.ModuleName] -> STM ()
+setFocusedModulesSTM ref modulesToFocus = do
+  setDurableStateSTM ref (IdeDurableState (Set.fromList modulesToFocus))
diff --git a/src/Language/PureScript/Ide/Types.hs b/src/Language/PureScript/Ide/Types.hs
index 41532a3c51..e51acc69a0 100644
--- a/src/Language/PureScript/Ide/Types.hs
+++ b/src/Language/PureScript/Ide/Types.hs
@@ -15,6 +15,7 @@ import Data.Aeson qualified as Aeson
 import Data.IORef (IORef)
 import Data.Time.Clock (UTCTime)
 import Data.Map.Lazy qualified as M
+import Data.Set qualified as S
 import Language.PureScript qualified as P
 import Language.PureScript.Errors.JSON qualified as P
 import Language.PureScript.Ide.Filter.Declaration (DeclarationType(..))
@@ -178,10 +179,11 @@ type Ide m = (MonadIO m, MonadReader IdeEnvironment m)
 data IdeState = IdeState
   { ideFileState :: IdeFileState
   , ideVolatileState :: IdeVolatileState
+  , ideDurableState :: IdeDurableState
   } deriving (Show)
 
 emptyIdeState :: IdeState
-emptyIdeState = IdeState emptyFileState emptyVolatileState
+emptyIdeState = IdeState emptyFileState emptyVolatileState emptyDurableState
 
 emptyFileState :: IdeFileState
 emptyFileState = IdeFileState M.empty M.empty
@@ -189,6 +191,8 @@ emptyFileState = IdeFileState M.empty M.empty
 emptyVolatileState :: IdeVolatileState
 emptyVolatileState = IdeVolatileState (AstData M.empty) M.empty Nothing
 
+emptyDurableState :: IdeDurableState
+emptyDurableState = IdeDurableState S.empty
 
 -- | @IdeFileState@ holds data that corresponds 1-to-1 to an entity on the
 -- filesystem. Externs correspond to the ExternsFiles the compiler emits into
@@ -213,6 +217,15 @@ data IdeVolatileState = IdeVolatileState
   , vsCachedRebuild :: Maybe (P.ModuleName, P.ExternsFile)
   } deriving (Show)
 
+-- | @IdeDurableState@ holds data that persists across resets of the @IdeState@.
+-- This is particularly useful for configuration variables that can be modified
+-- during runtime. For instance, the module names for the "focus" feature are 
+-- stored in the drFocusedModules field, which the client populates using the
+-- @Focus@ command to specify only which modules to load.
+data IdeDurableState = IdeDurableState
+  { drFocusedModules :: Set P.ModuleName
+  } deriving (Show)
+
 newtype Match a = Match (P.ModuleName, a)
            deriving (Show, Eq, Functor)
 
diff --git a/src/Language/PureScript/Linter/Exhaustive.hs b/src/Language/PureScript/Linter/Exhaustive.hs
index 697fefe8a0..eb03da41e0 100644
--- a/src/Language/PureScript/Linter/Exhaustive.hs
+++ b/src/Language/PureScript/Linter/Exhaustive.hs
@@ -11,7 +11,6 @@ module Language.PureScript.Linter.Exhaustive
 import Prelude
 import Protolude (ordNub)
 
-import Control.Applicative (Applicative(..))
 import Control.Arrow (first, second)
 import Control.Monad (unless)
 import Control.Monad.Writer.Class (MonadWriter(..))
diff --git a/src/Language/PureScript/Pretty/Types.hs b/src/Language/PureScript/Pretty/Types.hs
index 20de0ed9e2..9b3be46937 100644
--- a/src/Language/PureScript/Pretty/Types.hs
+++ b/src/Language/PureScript/Pretty/Types.hs
@@ -238,7 +238,7 @@ forall_ = mkPattern match
 typeAtomAsBox' :: PrettyPrintType -> Box
 typeAtomAsBox'
   = fromMaybe (internalError "Incomplete pattern")
-  . PA.pattern (matchTypeAtom defaultOptions) ()
+  . PA.pattern_ (matchTypeAtom defaultOptions) ()
 
 typeAtomAsBox :: Int -> Type a -> Box
 typeAtomAsBox maxDepth = typeAtomAsBox' . convertPrettyPrintType maxDepth
@@ -280,7 +280,7 @@ unicodeOptions = TypeRenderOptions False True False
 typeAsBoxImpl :: TypeRenderOptions -> PrettyPrintType -> Box
 typeAsBoxImpl tro
   = fromMaybe (internalError "Incomplete pattern")
-  . PA.pattern (matchType tro) ()
+  . PA.pattern_ (matchType tro) ()
 
 -- | Generate a pretty-printed string representing a 'Type'
 prettyPrintType :: Int -> Type a -> String
diff --git a/src/Language/PureScript/Sugar/BindingGroups.hs b/src/Language/PureScript/Sugar/BindingGroups.hs
index d2f9aebf2b..835e775f81 100644
--- a/src/Language/PureScript/Sugar/BindingGroups.hs
+++ b/src/Language/PureScript/Sugar/BindingGroups.hs
@@ -114,8 +114,8 @@ createBindingGroups moduleName = mapM f <=< handleDecls
 
       valueDeclarationInfo = M.fromList $ swap <$> valueDeclarationKeys
       findDeclarationInfo i = (M.findWithDefault False i valueDeclarationInfo, i)
-      computeValueDependencies = (`intersect` valueDeclarationKeys) . fmap findDeclarationInfo . usedIdents moduleName 
-  
+      computeValueDependencies = (`intersect` valueDeclarationKeys) . fmap findDeclarationInfo . usedIdents moduleName
+
       makeValueDeclarationVert = (,,) <$> id <*> makeValueDeclarationKey <*> computeValueDependencies
       valueDeclarationVerts = makeValueDeclarationVert <$> values
 
@@ -267,7 +267,7 @@ toDataBindingGroup
   -> m Declaration
 toDataBindingGroup (AcyclicSCC (d, _, _)) = return d
 toDataBindingGroup (CyclicSCC ds')
-  | Just kds@((ss, _):|_) <- nonEmpty $ concatMap (kindDecl . getDecl) ds' = throwError . errorMessage' ss . CycleInKindDeclaration $ fmap snd kds
+  | Just kds@((ss, _) :| _) <- nonEmpty $ concatMap (kindDecl . getDecl) ds' = throwError . errorMessage' ss . CycleInKindDeclaration $ fmap snd kds
   | not (null typeSynonymCycles) =
       throwError
         . MultipleErrors
diff --git a/src/Language/PureScript/TypeChecker/Monad.hs b/src/Language/PureScript/TypeChecker/Monad.hs
index b6382e6707..b33127200d 100644
--- a/src/Language/PureScript/TypeChecker/Monad.hs
+++ b/src/Language/PureScript/TypeChecker/Monad.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE GADTs #-}
+{-# LANGUAGE TypeOperators #-}
 
 -- |
 -- Monads for type checking and type inference and associated data types
diff --git a/src/Language/PureScript/TypeChecker/Synonyms.hs b/src/Language/PureScript/TypeChecker/Synonyms.hs
index 567ae415ef..8d2cf7886c 100644
--- a/src/Language/PureScript/TypeChecker/Synonyms.hs
+++ b/src/Language/PureScript/TypeChecker/Synonyms.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE GADTs #-}
+{-# LANGUAGE TypeOperators #-}
 
 -- |
 -- Functions for replacing fully applied type synonyms
diff --git a/stack.yaml b/stack.yaml
index 88b27b1a46..afbac89bca 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,6 +1,6 @@
 # Please update Haskell image versions under .github/workflows/ci.yml together to use the same GHC version
 # (or the CI build will fail)
-resolver: lts-20.26
+resolver: lts-22.43
 pvp-bounds: both
 packages:
 - '.'
@@ -13,20 +13,14 @@ extra-deps:
 # `async` to be used as an object key:
 # https://github.com/erikd/language-javascript/issues/131
 - language-javascript-0.7.0.0
-# Fix issue with libtinfo.
-# See https://github.com/purescript/purescript/issues/4253
-- process-1.6.13.1
-# The Cabal library is not in Stackage
-- Cabal-3.6.3.0
-# hspec versions 2.9.3 to 2.10.6 depend on ghc
-# ghc depends on terminfo by default, but that can be ignored
-# if one uses the '-terminfo' flag.
-# Unfortunately, hspec doesn't expose a similar flag.
-#
-# Using hspec >= 2.10.7 addresses this.
-- hspec-2.10.9
-- hspec-core-2.10.9
-- hspec-discover-2.10.9
+- bower-json-1.1.0.0
+- haskeline-0.8.2
+- these-1.2.1
+- aeson-better-errors-0.9.1.3
+
+- github: purescript/cheapskate
+  commit: 8bfaf4beeb108e97a274ed51303f278905979e87
+
 nix:
   packages:
   - zlib
@@ -37,8 +31,10 @@ nix:
 flags:
   aeson-pretty:
     lib-only: true
-  these:
-    assoc: false
   haskeline:
     # Avoids a libtinfo dynamic library dependency
     terminfo: false
+
+allow-newer: true
+allow-newer-deps:
+- haskeline
diff --git a/stack.yaml.lock b/stack.yaml.lock
new file mode 100644
index 0000000000..0af2cebb41
--- /dev/null
+++ b/stack.yaml.lock
@@ -0,0 +1,58 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/topics/lock_files
+
+packages:
+- completed:
+    hackage: language-javascript-0.7.0.0@sha256:3eab0262b8ac5621936a4beab6a0f97d0e00a63455a8b0e3ac1547b4088dae7d,3898
+    pantry-tree:
+      sha256: b0f28d836cb3fbde203fd7318a896c3a20acd8653a905e1950ae2d9a64bccebf
+      size: 2244
+  original:
+    hackage: language-javascript-0.7.0.0
+- completed:
+    hackage: bower-json-1.1.0.0@sha256:a136aaca67bf0d15c336f5864f7e9d40ebe046ca2cb4b25bc4895617ea35f9f6,1864
+    pantry-tree:
+      sha256: 3acd48e7012f246ad44c7c17cd6340362b1dc448c1d93156280814e76d9e0589
+      size: 419
+  original:
+    hackage: bower-json-1.1.0.0
+- completed:
+    hackage: haskeline-0.8.2@sha256:3b4b594095d64f5fa199b07bdca7d6b790313ed7f380a1b061845507e6563880,6005
+    pantry-tree:
+      sha256: 17ee6b093c5135399b8e6bc3a63d9c6a4b0bc2100b495d2d974bc1464769de39
+      size: 2955
+  original:
+    hackage: haskeline-0.8.2
+- completed:
+    hackage: these-1.2.1@sha256:35c57aede96c15ea1fed559ac287b1168eb2b2869d79e62ed8c845780b7ea136,2294
+    pantry-tree:
+      sha256: dc6366ac715dfdf5338a615f71b9ed0542c403a6afcbedcddbc879e947aea6b3
+      size: 351
+  original:
+    hackage: these-1.2.1
+- completed:
+    hackage: aeson-better-errors-0.9.1.3@sha256:1bfdda3982368cafc7317b9f0c1f7267a6b0bbac9515ae1fad37f2b19178f567,2071
+    pantry-tree:
+      sha256: 1c14247866dfb8052506c179e4725b8a7ce1472a4fb227d61576d862d9494551
+      size: 492
+  original:
+    hackage: aeson-better-errors-0.9.1.3
+- completed:
+    name: cheapskate
+    pantry-tree:
+      sha256: a2253619f50d26f0137a802e51e5e7103ee52b1f71bc060d93a0979dcbefa2c8
+      size: 12069
+    sha256: 959fc7a6ca7e0a743b06b0c287aa4a1c3ec7fc740e5830a4a841d43e925a6d73
+    size: 62502
+    url: https://github.com/purescript/cheapskate/archive/8bfaf4beeb108e97a274ed51303f278905979e87.tar.gz
+    version: 0.1.1.2
+  original:
+    url: https://github.com/purescript/cheapskate/archive/8bfaf4beeb108e97a274ed51303f278905979e87.tar.gz
+snapshots:
+- completed:
+    sha256: 08bd13ce621b41a8f5e51456b38d5b46d7783ce114a50ab604d6bbab0d002146
+    size: 720271
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/22/43.yaml
+  original: lts-22.43
diff --git a/update-changelog.hs b/update-changelog.hs
index b9296440d4..291160ceca 100755
--- a/update-changelog.hs
+++ b/update-changelog.hs
@@ -25,7 +25,8 @@
   , RecordWildCards
   , TupleSections
   , ViewPatterns
-#-}
+ #-} -- Hlint requires this leading space
+
 -- |
 -- This script updates CHANGELOG.md with the contents of CHANGELOG.d, and
 -- empties CHANGELOG.d. It takes care of:
diff --git a/weeder.dhall b/weeder.dhall
deleted file mode 100644
index 95686c45e8..0000000000
--- a/weeder.dhall
+++ /dev/null
@@ -1,41 +0,0 @@
-{ roots =
-  [ "^Main\\.main$"
-  , "^PscIdeSpec\\.main$"
-
-  -- These declarations are used in Pursuit. (The Types declarations are
-  -- reexported in the L.P.Docs module, and referenced from there, but Weeder
-  -- isn't that smart.)
-  , "^Language\\.PureScript\\.Docs\\.AsHtml\\.packageAsHtml$"
-  , "^Language\\.PureScript\\.Docs\\.Types\\.asUploadedPackage$"
-  , "^Language\\.PureScript\\.Docs\\.Types\\.getLink$"
-  , "^Language\\.PureScript\\.Docs\\.Types\\.getLinksContext$"
-  , "^Language\\.PureScript\\.Docs\\.Types\\.packageName$"
-  , "^Language\\.PureScript\\.Docs\\.Types\\.verifyPackage$"
-
-  -- These declarations are believed to be used in other projects that we want
-  -- to continue to support.
-  , "^Language\\.PureScript\\.CoreFn\\.FromJSON\\.moduleFromJSON$"
-  , "^Language\\.PureScript\\.CST\\.Print\\.printModule$"
-
-  -- These declarations are there to be used during development or testing.
-  , "^Language\\.PureScript\\.Ide\\.Imports\\.parseImport$"
-  , "^Language\\.PureScript\\.TypeChecker\\.Monad\\.debug"
-
-  -- These declarations are used by Template Haskell code.
-  , "^Language\\.PureScript\\.Constants\\.TH\\."
-
-  -- These declarations are produced by Template Haskell when generating
-  -- pattern synonyms; this confuses Weeder.
-  , "^Language\\.PureScript\\.Constants\\..*\\.\\$[bm]"
-
-  -- These declarations are unprincipled exceptions that we don't mind
-  -- supporting just in case they're used now or in the future.
-  , "^Language\\.PureScript\\.CST\\.Parser\\.parseExpr$"
-
-  -- These declarations are generated by tools; it doesn't matter if they're
-  -- unused because we can't do anything about them.
-  , "^Language\\.PureScript\\.CST\\.Parser\\.happy"
-  , "^Paths_purescript?\\."
-  ]
-, type-class-roots = True
-}
diff --git a/weeder.toml b/weeder.toml
new file mode 100644
index 0000000000..1a8249a2e2
--- /dev/null
+++ b/weeder.toml
@@ -0,0 +1,40 @@
+roots = [
+  "^Main\\.main$",
+  "^PscIdeSpec\\.main$",
+
+  # These declarations are used in Pursuit. (The Types declarations are
+  # reexported in the L.P.Docs module, and referenced from there, but Weeder
+  # isn't that smart.)
+  "^Language\\.PureScript\\.Docs\\.AsHtml\\.packageAsHtml$",
+  "^Language\\.PureScript\\.Docs\\.Types\\.asUploadedPackage$",
+  "^Language\\.PureScript\\.Docs\\.Types\\.getLink$",
+  "^Language\\.PureScript\\.Docs\\.Types\\.getLinksContext$",
+  "^Language\\.PureScript\\.Docs\\.Types\\.packageName$",
+  "^Language\\.PureScript\\.Docs\\.Types\\.verifyPackage$",
+
+  # These declarations are believed to be used in other projects that we want
+  # to continue to support.
+  "^Language\\.PureScript\\.CoreFn\\.FromJSON\\.moduleFromJSON$",
+  "^Language\\.PureScript\\.CST\\.Print\\.printModule$",
+
+  # These declarations are there to be used during development or testing.
+  "^Language\\.PureScript\\.Ide\\.Imports\\.parseImport$",
+  "^Language\\.PureScript\\.TypeChecker\\.Monad\\.debug",
+
+  # These declarations are used by Template Haskell code.
+  "^Language\\.PureScript\\.Constants\\.TH\\.",
+
+  # These declarations are produced by Template Haskell when generating
+  # pattern synonyms; this confuses Weeder.
+  "^Language\\.PureScript\\.Constants\\..*\\.\\$[bm]",
+
+  # These declarations are unprincipled exceptions that we don't mind
+  # supporting just in case they're used now or in the future.
+  "^Language\\.PureScript\\.CST\\.Parser\\.parseExpr$",
+
+  # These declarations are generated by tools; it doesn't matter if they're
+  # unused because we can't do anything about them.
+  "^Language\\.PureScript\\.CST\\.Parser\\.happy",
+  "^Paths_purescript?\\.",
+]
+type-class-roots = true