diff --git a/.circleci/config.yml b/.circleci/config.yml
index cabf68d6b0..16e38ab318 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -103,6 +103,11 @@ jobs:
       - STACK_FILE: "stack-8.10.4.yaml"
     <<: *defaults
 
+  ghc-8.10.5:
+    environment:
+      - STACK_FILE: "stack-8.10.5.yaml"
+    <<: *defaults
+
   ghc-9.0.1:
     environment:
       - STACK_FILE: "stack-9.0.1.yaml"
@@ -126,5 +131,6 @@ workflows:
       - ghc-8.10.2
       - ghc-8.10.3
       - ghc-8.10.4
+      - ghc-8.10.5
       - ghc-9.0.1
       - ghc-default
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 70d49f958c..ae64e4907b 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ghc: ['8.10.4', '8.10.3', '8.10.2', '8.8.4', '8.8.3', '8.8.2', '8.6.5', '8.6.4']
+        ghc: ['8.10.5', '8.10.4', '8.10.3', '8.10.2', '8.8.4', '8.8.3', '8.8.2', '8.6.5', '8.6.4']
         os: [ubuntu-18.04, macOS-latest, windows-latest]
         exclude:
           - os: windows-latest
@@ -27,6 +27,8 @@ jobs:
             ghc: '8.8.3' # fails due to segfault
           - os: windows-latest
             ghc: '8.8.2' # fails due to error with Cabal
+          - os: macOS-latest
+            ghc: '8.10.5' # https://gitlab.haskell.org/ghc/ghc/-/issues/19968
         include:
           - os: windows-latest
             ghc: '8.10.2.2' # only available for windows and choco
@@ -113,11 +115,11 @@ jobs:
         path: ${{ steps.compress_server_binary.outputs.path }}
 
     - name: Build Wrapper
-      if: matrix.ghc == '8.10.4'
+      if: matrix.ghc == '8.10.5'
       run: cabal build exe:hls-wrapper -O2 $LINUX_CABAL_ARGS
 
     - name: Compress Wrapper Binary
-      if: matrix.ghc == '8.10.4'
+      if: matrix.ghc == '8.10.5'
       id: compress_wrapper_binary
       run: |
         HLS_WRAPPER_BUILD=$(find dist-newstyle \( -name 'hls-wrapper' -o -name 'hls-wrapper.exe' \) -type f)
@@ -136,7 +138,7 @@ jobs:
         fi
 
     - name: Upload Wrapper
-      if: matrix.ghc == '8.10.4'
+      if: matrix.ghc == '8.10.5'
       uses: actions/upload-release-asset@v1.0.2
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
@@ -147,7 +149,7 @@ jobs:
         asset_content_type: ${{ steps.compress_wrapper_binary.outputs.content_type}}
 
     - uses: actions/upload-artifact@v2
-      if: matrix.ghc == '8.10.4'
+      if: matrix.ghc == '8.10.5'
       with:
         name: haskell-language-server-wrapper-${{ runner.OS }}${{env.EXE_EXT}}.${{ steps.compress_wrapper_binary.outputs.extension }}
         path: ${{ steps.compress_wrapper_binary.outputs.path }}
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 34f7d4860b..9637180800 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -33,7 +33,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        ghc: ["9.0.1", "8.10.4", "8.10.3", "8.10.2", "8.8.4", "8.8.3", "8.8.2", "8.6.5", "8.6.4"]
+        ghc: ["9.0.1", "8.10.5", "8.10.4", "8.10.3", "8.10.2", "8.8.4", "8.8.3", "8.8.2", "8.6.5", "8.6.4"]
         os: [ubuntu-latest, macOS-latest]
         include:
           # only test supported ghc major versions
@@ -41,10 +41,7 @@ jobs:
             ghc: '9.0.1'
             test: true
           - os: ubuntu-latest
-            ghc: '8.10.4'
-            test: true
-          - os: windows-latest
-            ghc: '8.10.4'
+            ghc: '8.10.5'
             test: true
           - os: ubuntu-latest
             ghc: '8.8.4'
@@ -52,17 +49,28 @@ jobs:
           - os: ubuntu-latest
             ghc: '8.6.5'
             test: true
+          # only build rest of supported ghc versions for windows
+          # Disable window test temporarily because choco does not have GHC 8.10.5 yet
           - os: windows-latest
-            ghc: '8.6.5'
+            ghc: '8.10.5'
             test: true
-          # only build rest of supported ghc versions for windows
           - os: windows-latest
-            ghc: '8.10.2.2'
+            ghc: '8.10.4'
           - os: windows-latest
             ghc: '8.10.3'
+          - os: windows-latest
+            ghc: '8.10.2.2'
+          - os: windows-latest
+            ghc: '8.6.5'
+            test: true
           # This build get stuck frequently
           # - os: windows-latest
           #   ghc: '8.6.4'
+        exclude:
+          # Not able to build 'network' package
+          # See https://gitlab.haskell.org/ghc/ghc/-/issues/19968
+          - os: macOS-latest
+            ghc: '8.10.5'
 
     steps:
       - if: ${{ needs.pre_job.outputs.should_skip != 'true' }}
diff --git a/cabal-ghc901.project b/cabal-ghc901.project
index 017783b414..a293fa508d 100644
--- a/cabal-ghc901.project
+++ b/cabal-ghc901.project
@@ -51,7 +51,7 @@ source-repository-package
 source-repository-package
   type: git
   location: https://github.com/hsyl20/ghc-api-compat
-  tag: 6178d75772c7d923918dfffa0b1f503dfb36d0a6
+  tag: 8fee87eac97a538dbe81ff1ab18cff10f2f9fa15
 
 source-repository-package
   type: git
diff --git a/cabal.project b/cabal.project
index 26b29981e7..d198b487b8 100644
--- a/cabal.project
+++ b/cabal.project
@@ -28,6 +28,12 @@ package *
   ghc-options: -haddock
   test-show-details: direct
 
+-- ghc-api-compat-8.6
+source-repository-package
+  type: git
+  location: https://github.com/hsyl20/ghc-api-compat
+  tag: 8fee87eac97a538dbe81ff1ab18cff10f2f9fa15
+
 write-ghc-environment-files: never
 
 index-state: 2021-05-21T05:01:41Z
diff --git a/flake.nix b/flake.nix
index 604f909b51..677f0a5c76 100644
--- a/flake.nix
+++ b/flake.nix
@@ -167,6 +167,7 @@
           pkgs.haskellPackages.ghc.version);
         ghc884 = pkgs.hlsHpkgs "ghc884";
         ghc8104 = pkgs.hlsHpkgs "ghc8104";
+        ghc8105 = pkgs.hlsHpkgs "ghc8105";
         ghc901 = pkgs.hlsHpkgs "ghc901";
 
         # Create a development shell of hls project
@@ -216,12 +217,14 @@
           haskell-language-server-dev = mkDevShell ghcDefault;
           haskell-language-server-884-dev = mkDevShell ghc884;
           haskell-language-server-8104-dev = mkDevShell ghc8104;
+          haskell-language-server-8105-dev = mkDevShell ghc8105;
           haskell-language-server-901-dev = mkDevShell ghc901;
 
           # hls package
           haskell-language-server = mkExe ghcDefault;
           haskell-language-server-884 = mkExe ghc884;
           haskell-language-server-8104 = mkExe ghc8104;
+          haskell-language-server-8105 = mkExe ghc8105;
           haskell-language-server-901 = mkExe ghc901;
         };
 
diff --git a/ghcide/ghcide.cabal b/ghcide/ghcide.cabal
index dc41bb9999..20aedb7f92 100644
--- a/ghcide/ghcide.cabal
+++ b/ghcide/ghcide.cabal
@@ -13,7 +13,7 @@ description:
     A library for building Haskell IDE's on top of the GHC API.
 homepage:           https://github.com/haskell/haskell-language-server/tree/master/ghcide#readme
 bug-reports:        https://github.com/haskell/haskell-language-server/issues
-tested-with:        GHC == 8.6.4 || == 8.6.5 || == 8.8.2 || == 8.8.3 || == 8.8.4 || == 8.10.2 || == 8.10.3 || == 8.10.4 || == 9.0.1
+tested-with:        GHC == 8.6.4 || == 8.6.5 || == 8.8.2 || == 8.8.3 || == 8.8.4 || == 8.10.2 || == 8.10.3 || == 8.10.4 || == 8.10.5 || == 9.0.1
 extra-source-files: README.md CHANGELOG.md
                     test/data/**/*.project
                     test/data/**/*.cabal
diff --git a/ghcide/test/exe/Main.hs b/ghcide/test/exe/Main.hs
index ede8f20822..3c0db29088 100644
--- a/ghcide/test/exe/Main.hs
+++ b/ghcide/test/exe/Main.hs
@@ -3653,6 +3653,9 @@ checkFileCompiles fp diag =
 pluginSimpleTests :: TestTree
 pluginSimpleTests =
   ignoreInWindowsForGHC88And810 $
+#if __GLASGOW_HASKELL__ == 810 && __GLASGOW_HASKELL_PATCHLEVEL1__ == 5
+  expectFailBecause "known broken (see GHC #19763)" $
+#endif
   testSessionWithExtraFiles "plugin-knownnat" "simple plugin" $ \dir -> do
     _ <- openDoc (dir </> "KnownNat.hs") "haskell"
     liftIO $ writeFile (dir</>"hie.yaml")
diff --git a/haskell-language-server.cabal b/haskell-language-server.cabal
index f9ad2379f6..50424693ac 100644
--- a/haskell-language-server.cabal
+++ b/haskell-language-server.cabal
@@ -14,7 +14,7 @@ copyright:          The Haskell IDE Team
 license:            Apache-2.0
 license-file:       LICENSE
 build-type:         Simple
-tested-with:        GHC == 8.6.4 || == 8.6.5 || == 8.8.2 || == 8.8.3 || == 8.8.4 || == 8.10.2 || == 8.10.3 || == 8.10.4
+tested-with:        GHC == 8.6.4 || == 8.6.5 || == 8.8.2 || == 8.8.3 || == 8.8.4 || == 8.10.2 || == 8.10.3 || == 8.10.4 || == 8.10.5
 extra-source-files:
   README.md
   ChangeLog.md
diff --git a/stack-8.10.2.yaml b/stack-8.10.2.yaml
index 7475853df9..ce833e756a 100644
--- a/stack-8.10.2.yaml
+++ b/stack-8.10.2.yaml
@@ -36,7 +36,9 @@ extra-deps:
   - data-tree-print-0.1.0.2@rev:2
   - floskell-0.10.4
   - fourmolu-0.3.0.0
-  - ghc-api-compat-8.6
+  - # ghc-api-compat-8.6
+    github: hsyl20/ghc-api-compat
+    commit: 8fee87eac97a538dbe81ff1ab18cff10f2f9fa15
   - ghc-check-0.5.0.4
   - ghc-exactprint-0.6.4
   - ghc-lib-8.10.4.20210206
diff --git a/stack-8.10.3.yaml b/stack-8.10.3.yaml
index c3d2ffa67c..250c3c0d31 100644
--- a/stack-8.10.3.yaml
+++ b/stack-8.10.3.yaml
@@ -36,7 +36,9 @@ extra-deps:
   - data-tree-print-0.1.0.2@rev:2
   - floskell-0.10.4
   - fourmolu-0.3.0.0
-  - ghc-api-compat-8.6
+  - # ghc-api-compat-8.6
+    github: hsyl20/ghc-api-compat
+    commit: 8fee87eac97a538dbe81ff1ab18cff10f2f9fa15
   - ghc-check-0.5.0.4
   - ghc-exactprint-0.6.4
   - ghc-lib-8.10.4.20210206
diff --git a/stack-8.10.4.yaml b/stack-8.10.4.yaml
index 7c7f25ddeb..bcfad67469 100644
--- a/stack-8.10.4.yaml
+++ b/stack-8.10.4.yaml
@@ -36,7 +36,9 @@ extra-deps:
   - data-tree-print-0.1.0.2@rev:2
   - floskell-0.10.4
   - fourmolu-0.3.0.0
-  - ghc-api-compat-8.6
+  - # ghc-api-compat-8.6
+    github: hsyl20/ghc-api-compat
+    commit: 8fee87eac97a538dbe81ff1ab18cff10f2f9fa15
   - ghc-check-0.5.0.4
   - ghc-exactprint-0.6.4
   - heapsize-0.3.0
diff --git a/stack-8.10.5.yaml b/stack-8.10.5.yaml
new file mode 100644
index 0000000000..094d96c1d2
--- /dev/null
+++ b/stack-8.10.5.yaml
@@ -0,0 +1,98 @@
+# Fixme once GHC-8.10.5 LTS is out
+resolver: nightly-2021-06-01
+compiler: ghc-8.10.5
+
+packages:
+  - .
+  - ./hie-compat
+  - ./hls-graph
+  - ./ghcide/
+  - ./hls-plugin-api
+  - ./hls-test-utils
+  # - ./shake-bench
+  - ./plugins/hls-class-plugin
+  - ./plugins/hls-haddock-comments-plugin
+  - ./plugins/hls-eval-plugin
+  - ./plugins/hls-explicit-imports-plugin
+  - ./plugins/hls-refine-imports-plugin
+  - ./plugins/hls-hlint-plugin
+  - ./plugins/hls-retrie-plugin
+  - ./plugins/hls-splice-plugin
+  - ./plugins/hls-tactics-plugin
+  - ./plugins/hls-brittany-plugin
+  - ./plugins/hls-stylish-haskell-plugin
+  - ./plugins/hls-floskell-plugin
+  - ./plugins/hls-fourmolu-plugin
+  - ./plugins/hls-pragmas-plugin
+  - ./plugins/hls-module-name-plugin
+  - ./plugins/hls-ormolu-plugin
+
+ghc-options:
+  "$everything": -haddock
+
+extra-deps:
+  - apply-refact-0.9.3.0
+  - brittany-0.13.1.2
+  - Cabal-3.0.2.0
+  - clock-0.7.2
+  - data-tree-print-0.1.0.2@rev:2
+  - floskell-0.10.5
+  - fourmolu-0.3.0.0
+  - # ghc-api-compat-8.6
+    github: hsyl20/ghc-api-compat
+    commit: 8fee87eac97a538dbe81ff1ab18cff10f2f9fa15
+  - ghc-check-0.5.0.4
+  - ghc-exactprint-0.6.4
+  - heapsize-0.3.0
+  - implicit-hie-cradle-0.3.0.2
+  - implicit-hie-0.1.2.5
+  - monad-dijkstra-0.1.1.2
+  - refinery-0.3.0.0
+  - retrie-1.0.0.0
+  - stylish-haskell-0.12.2.0
+  - semigroups-0.18.5
+  - temporary-1.2.1.1
+  - th-compat-0.1.2@sha256:3d55de1adc542c1a870c9ada90da2fbbe5f4e8bcd3eed545a55c3df9311b32a8,2854
+  - bytestring-encoding-0.1.0.0@sha256:460b49779fbf0112e8e2f1753c1ed9131eb18827600c298f4d6bb51c4e8c1c0d,1727
+  - hiedb-0.3.0.1
+  - lsp-1.2.0.0
+  - lsp-types-1.2.0.0
+  - lsp-test-0.14.0.0
+  - dependent-map-0.4.0.0@sha256:ca2b131046f4340a1c35d138c5a003fe4a5be96b14efc26291ed35fd08c62221,1657
+  - dependent-sum-0.7.1.0@sha256:5599aa89637db434431b1dd3fa7c34bc3d565ee44f0519bfbc877be1927c2531,2068
+  - dependent-sum-template-0.1.0.3@sha256:0bbbacdfbd3abf2a15aaf0cf2c27e5bdd159b519441fec39e1e6f2f54424adde,1682
+  - constraints-extras-0.3.1.0
+  - some-1.0.1@sha256:26e5bab7276f48b25ea8660d3fd1166c0f20fd497dac879a40f408e23211f93e,2055
+  - unliftio-core-0.2.0.1@sha256:9b3e44ea9aacacbfc35b3b54015af450091916ac3618a41868ebf6546977659a,1082
+
+  # Enable these when supported by all formatters
+  # - ghc-lib-9.0.1.20210324@sha256:c8b9a2541ea3424c8d0e4f80584477d0f35be03f4a47d931152042d5f446c5fc,19279
+  # - ghc-lib-parser-9.0.1.20210324@sha256:fb680f78d4ab08b5d089a05bda3b84ad857e5edcc2e4ca7c188c0207d369af80
+  # - ghc-lib-parser-ex-9.0.0.4@sha256:8282b11c3797fc8ba225b245e736cc9a0745d9c48d0f9fea7f9bffb5c9997709,3642
+  # - hlint-3.3@sha256:4218ad6e03050f5d68aeba0e025f5f05e366c8fd49657f2a19df04ee31b2bb23,4154
+
+configure-options:
+  ghcide:
+      - --disable-library-for-ghci
+  haskell-language-server:
+      - --disable-library-for-ghci
+  heapsize:
+      - --disable-library-for-ghci
+
+flags:
+  haskell-language-server:
+    pedantic: true
+  retrie:
+    BuildExecutable: false
+  # Stack doesn't support automatic flags.
+  # Until the formatters support ghc-lib-9, we need this flag disabled
+  hls-hlint-plugin:
+    hlint33: false
+
+# Because of implicit-hie-cradle-0.3.0.2 and stylish-haskell-0.12.2.0
+allow-newer: true
+
+nix:
+  packages: [ icu libcxx zlib ]
+
+concurrent-tests: false
diff --git a/stack-8.6.4.yaml b/stack-8.6.4.yaml
index 57f52c0428..548297d594 100644
--- a/stack-8.6.4.yaml
+++ b/stack-8.6.4.yaml
@@ -43,7 +43,9 @@ extra-deps:
   - floskell-0.10.4
   - fourmolu-0.3.0.0
   - fuzzy-0.1.0.0
-  - ghc-api-compat-8.6
+  - # ghc-api-compat-8.6
+    github: hsyl20/ghc-api-compat
+    commit: 8fee87eac97a538dbe81ff1ab18cff10f2f9fa15
   - ghc-check-0.5.0.4
   - ghc-events-0.13.0
   - ghc-exactprint-0.6.4
diff --git a/stack-8.6.5.yaml b/stack-8.6.5.yaml
index 257d5c4274..44c8193f32 100644
--- a/stack-8.6.5.yaml
+++ b/stack-8.6.5.yaml
@@ -44,7 +44,9 @@ extra-deps:
   - floskell-0.10.4
   - fourmolu-0.3.0.0
   - fuzzy-0.1.0.0
-  - ghc-api-compat-8.6
+  - # ghc-api-compat-8.6
+    github: hsyl20/ghc-api-compat
+    commit: 8fee87eac97a538dbe81ff1ab18cff10f2f9fa15
   - ghc-check-0.5.0.4
   - ghc-events-0.13.0
   - ghc-exactprint-0.6.4
diff --git a/stack-8.8.2.yaml b/stack-8.8.2.yaml
index 06f346efe1..bc4a3441e7 100644
--- a/stack-8.8.2.yaml
+++ b/stack-8.8.2.yaml
@@ -38,7 +38,9 @@ extra-deps:
   - constrained-dynamic-0.1.0.0
   - floskell-0.10.4
   - fourmolu-0.3.0.0
-  - ghc-api-compat-8.6
+  - # ghc-api-compat-8.6
+    github: hsyl20/ghc-api-compat
+    commit: 8fee87eac97a538dbe81ff1ab18cff10f2f9fa15
   - ghc-check-0.5.0.4
   - ghc-events-0.13.0
   - ghc-exactprint-0.6.4
diff --git a/stack-8.8.3.yaml b/stack-8.8.3.yaml
index 8f706b0099..3788c4d617 100644
--- a/stack-8.8.3.yaml
+++ b/stack-8.8.3.yaml
@@ -38,7 +38,9 @@ extra-deps:
   - constrained-dynamic-0.1.0.0
   - floskell-0.10.4
   - fourmolu-0.3.0.0
-  - ghc-api-compat-8.6
+  - # ghc-api-compat-8.6
+    github: hsyl20/ghc-api-compat
+    commit: 8fee87eac97a538dbe81ff1ab18cff10f2f9fa15
   - ghc-check-0.5.0.4
   - ghc-exactprint-0.6.4
   - ghc-lib-8.10.4.20210206
diff --git a/stack-8.8.4.yaml b/stack-8.8.4.yaml
index 1a0fe87220..9fb15da735 100644
--- a/stack-8.8.4.yaml
+++ b/stack-8.8.4.yaml
@@ -38,7 +38,9 @@ extra-deps:
   - constrained-dynamic-0.1.0.0
   - floskell-0.10.4
   - fourmolu-0.3.0.0
-  - ghc-api-compat-8.6
+  - # ghc-api-compat-8.6
+    github: hsyl20/ghc-api-compat
+    commit: 8fee87eac97a538dbe81ff1ab18cff10f2f9fa15
   - ghc-check-0.5.0.4
   - ghc-exactprint-0.6.4
   - ghc-lib-8.10.4.20210206
diff --git a/stack-9.0.1.yaml b/stack-9.0.1.yaml
index 452167ea1b..086bd185d8 100644
--- a/stack-9.0.1.yaml
+++ b/stack-9.0.1.yaml
@@ -68,7 +68,7 @@ extra-deps:
 # https://github.com/mpickering/hie-bios/pull/285
 
 - github: hsyl20/ghc-api-compat
-  commit: 6178d75772c7d923918dfffa0b1f503dfb36d0a6
+  commit: 8fee87eac97a538dbe81ff1ab18cff10f2f9fa15
 
 - github: anka-213/th-extras
   commit: 57a97b4df128eb7b360e8ab9c5759392de8d1659