diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3fcb9490..b5d2dd75 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,13 +18,14 @@ jobs:
         cabal: ["latest"]
         ghc:
           - "8.8.4"
-          - "8.10.2"
+          - "8.10.2" # doctests are disabled on 8.10.3, but still working on 8.10.2.
+          - "8.10.3"
 
     steps:
     - uses: actions/checkout@v2
       #if: github.event.action == 'opened' || github.event.action == 'synchronize' || github.event.ref == 'refs/heads/master'
 
-    - uses: actions/setup-haskell@v1.1
+    - uses: haskell/actions/setup@v1
       id: setup-haskell-cabal
       name: Setup Haskell
       with:
@@ -59,10 +60,11 @@ jobs:
     - uses: actions/checkout@v2
       #if: github.event.action == 'opened' || github.event.action == 'synchronize' || github.event.ref == 'refs/heads/master'
 
-    - uses: actions/setup-haskell@v1.1
+    - uses: haskell/actions/setup@v1
       name: Setup Haskell Stack
       with:
         stack-version: ${{ matrix.stack }}
+        enable-stack: true
 
     - uses: actions/cache@v1
       name: Cache ~/.stack
@@ -85,7 +87,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - uses: cachix/install-nix-action@v10
+    - uses: cachix/install-nix-action@v12
       with:
         nix_path: nixpkgs=channel:nixos-unstable
     - run: nix-build
diff --git a/.nix-helpers/nixpkgs.nix b/.nix-helpers/nixpkgs.nix
index b9c75db1..7e815895 100644
--- a/.nix-helpers/nixpkgs.nix
+++ b/.nix-helpers/nixpkgs.nix
@@ -26,13 +26,13 @@ let
     if isNull nixpkgs
       then
         builtins.fetchTarball {
-          # Recent version of nixpkgs master as of 2020-08-18 which uses LTS-16.9.
-          url = "https://github.com/NixOS/nixpkgs/archive/c5815280e92112a25d958a2ec8b3704d7d90c506.tar.gz";
-          sha256 = "09ic4s9s7w3lm0gmcxszm5j20cfv4n5lfvhdvgi7jzdbbbdps1nh";
+          # Recent version of nixpkgs master as of 2020-12-27 which uses nightly-2020-12-14.
+          url = "https://github.com/NixOS/nixpkgs/archive/84917aa00bf23c88e5874c683abe05edb0ba4078.tar.gz";
+          sha256 = "1x3qh815d7k9yc72zpn5cfaaq2b1942q4pka6rx8b5i33yz4m61q";
         }
       else nixpkgs;
 
-  compilerVersion = if isNull compiler then "ghc884" else compiler;
+  compilerVersion = if isNull compiler then "ghc8103" else compiler;
 
   # An overlay that adds termonad to all haskell package sets.
   haskellPackagesOverlay = self: super: {
@@ -66,7 +66,10 @@ let
                   src
                   extraCabal2nixOptions
                   {
-                    inherit (self) gtk3;
+                    # There are Haskell packages called gtk3 and pcre2, which
+                    # makes these system dependencies not able to be resolved
+                    # correctly.
+                    inherit (self) gtk3 pcre2;
                     vte_291 = self.vte;
                   };
             in
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 50f91953..7f26a0cc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 4.0.1.2
+
+*   Disable doctest test-suite when building with GHC-8.10.3.  The doctests
+    appear to be segfaulting, but only when compiled with GHC-8.10.3.
+    [#175](https://github.com/cdepillabout/termonad/pull/175).
+
 ## 4.0.1.1
 
 *   Bump upper dependency on `base` so that Termonad is compatible with
diff --git a/stack-nightly.yaml b/stack-nightly.yaml
new file mode 100644
index 00000000..6e0ba39a
--- /dev/null
+++ b/stack-nightly.yaml
@@ -0,0 +1,42 @@
+# For more information, see: http://docs.haskellstack.org/en/stable/yaml_configuration.html
+
+# Specifies the GHC version and set of packages available (e.g., lts-3.5, nightly-2015-09-21, ghc-7.10.2)
+resolver: nightly-2020-12-14
+
+# Local packages, usually specified by relative directory name
+packages:
+    - '.'
+
+# Packages to be pulled from upstream that are not in the resolver (e.g., acme-missiles-0.3)
+extra-deps:
+  - gi-vte-2.91.27@sha256:22faf2c2333ca2fe90780d44defcc7b095c619b72f27b90c9de1f5e2a960a5e3,3731
+  - xml-html-qq-0.1.0.1@sha256:1e6dc32d764da2b80eed8809cdbee0cb1f57011fa95ad1d8fe5949c4d8bde568,2331
+
+# Override default flag values for local packages and extra-deps
+flags: {}
+
+# Extra package databases containing global packages
+extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: >= 1.0.0
+
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor
+
+nix:
+    packages: []
+    pure: true
+    shell-file: .nix-helpers/stack-shell.nix
diff --git a/stack-nightly.yaml.lock b/stack-nightly.yaml.lock
new file mode 100644
index 00000000..46c7925e
--- /dev/null
+++ b/stack-nightly.yaml.lock
@@ -0,0 +1,26 @@
+# 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/lock_files
+
+packages:
+- completed:
+    hackage: gi-vte-2.91.27@sha256:22faf2c2333ca2fe90780d44defcc7b095c619b72f27b90c9de1f5e2a960a5e3,3731
+    pantry-tree:
+      size: 356
+      sha256: 2bfa50f6abba8feda2a8b5b1a36c589562d4f31ecc3c351239bdd3b4454c4458
+  original:
+    hackage: gi-vte-2.91.27@sha256:22faf2c2333ca2fe90780d44defcc7b095c619b72f27b90c9de1f5e2a960a5e3,3731
+- completed:
+    hackage: xml-html-qq-0.1.0.1@sha256:1e6dc32d764da2b80eed8809cdbee0cb1f57011fa95ad1d8fe5949c4d8bde568,2331
+    pantry-tree:
+      size: 499
+      sha256: 4bc9e68d9470b2d37eddc97235700c1a7fb7b64740f3ba4d3196ff4f16973676
+  original:
+    hackage: xml-html-qq-0.1.0.1@sha256:1e6dc32d764da2b80eed8809cdbee0cb1f57011fa95ad1d8fe5949c4d8bde568,2331
+snapshots:
+- completed:
+    size: 558061
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/nightly/2020/12/14.yaml
+    sha256: 0c80697b1db876c0ab31b43e42be53f886657a336eca59c73c361078e631d65b
+  original: nightly-2020-12-14
diff --git a/termonad.cabal b/termonad.cabal
index 816e7b77..049a51fc 100644
--- a/termonad.cabal
+++ b/termonad.cabal
@@ -1,5 +1,5 @@
 name:                termonad
-version:             4.0.1.1
+version:             4.0.1.2
 synopsis:            Terminal emulator configurable in Haskell
 description:
   Termonad is a terminal emulator configurable in Haskell.  It is extremely
@@ -147,8 +147,15 @@ test-suite doctests
                      , doctest
                      , QuickCheck
                      , template-haskell
+                     , termonad
   default-language:    Haskell2010
   ghc-options:         -Wall -threaded -rtsopts -with-rtsopts=-N
+  -- For some reason doctests appear to be segfaulting when compiling with
+  -- ghc-8.10.3, so only build them when using ghc-8.10.2 or earlier.
+  if impl(ghc <= 8.10.2)
+    buildable:         True
+  else
+    buildable:         False
 
 test-suite termonad-test
   type:                exitcode-stdio-1.0