diff --git a/.github/workflows/binaries-linux-x64.yml b/.github/workflows/binaries-linux-x64.yml
index e082d0a75..35be03bcf 100644
--- a/.github/workflows/binaries-linux-x64.yml
+++ b/.github/workflows/binaries-linux-x64.yml
@@ -30,26 +30,25 @@ jobs:
       run: |
         apk --no-cache add gmp-dev gmp-static libffi-dev zlib-dev zlib-static ncurses-dev ncurses-static binutils-gold curl gcc g++ git make xz tar perl
 
-    # things to be cached/restored (needs tar)
+    # CACHES
 
     - name: Cache - ~/.ghcup
       id:   ghcup
       uses: actions/cache@v4
       with:
         path: ~/.ghcup
-        key: ${{ runner.os }}-ghcup-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-ghcup-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-ghcup
+             ${{ runner.os }}-x64-ghcup-${{ env.ghc }}
 
-    # XXX Warning: Path Validation Error: Path(s) specified in the action for caching do(es) not exist, hence no cache is being saved.
     - name: Cache - ~/.cabal
       id:   cabal
       uses: actions/cache@v4
       with:
         path: ~/.cabal
-        key: ${{ runner.os }}-cabal-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-cabal-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-cabal
+             ${{ runner.os }}-x64-cabal-${{ env.ghc }}
 
     # actions:
 
diff --git a/.github/workflows/binaries-mac-arm64.yml b/.github/workflows/binaries-mac-arm64.yml
index e32fe9e12..030e70bea 100644
--- a/.github/workflows/binaries-mac-arm64.yml
+++ b/.github/workflows/binaries-mac-arm64.yml
@@ -34,67 +34,65 @@ jobs:
       run: |
         tools/checkembeddedfiles
 
-    # caching
-    # XXX Should some of these have ghc version in the key, as in ci.yml ?
-    # I think so, otherwise when ghc version changes they'll keep restoring the old data and it won't be used or updated
+    # CACHES
 
     - name: Cache - stack-installed ~/.local/bin
       id:   stack-programs
       uses: actions/cache@v4
       with:
         path: ~/.local/bin
-        key: ${{ runner.os }}-arm64-stack-programs-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-arm64-stack-programs-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-arm64-stack-programs
+             ${{ runner.os }}-arm64-stack-programs-${{ env.ghc }}
 
     - name: Cache - ~/.stack
       id:   stack-global
       uses: actions/cache@v4
       with:
         path: ~/.stack
-        key: ${{ runner.os }}-arm64-stack-global-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-arm64-stack-global-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-arm64-stack-global
+             ${{ runner.os }}-arm64-stack-global-${{ env.ghc }}
 
     - name: Cache - ./.stack-work
       uses: actions/cache@v4
       with:
         path: .stack-work
-        key: ${{ runner.os }}-arm64-stack-work-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-arm64-stack-work-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-arm64-stack-work
+             ${{ runner.os }}-arm64-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger-lib/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-lib/.stack-work
-        key: ${{ runner.os }}-arm64-hledger-lib-stack-work-${{ hashFiles('hledger-lib/package.yaml') }}
+        key: ${{ runner.os }}-arm64-hledger-lib-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-lib/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-arm64-hledger-lib-stack-work
+             ${{ runner.os }}-arm64-hledger-lib-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger/.stack-work
-        key: ${{ runner.os }}-arm64-hledger-stack-work-${{ hashFiles('hledger/package.yaml') }}
+        key: ${{ runner.os }}-arm64-hledger-stack-work-${{ env.ghc }}-${{ hashFiles('hledger/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-arm64-hledger-stack-work
+             ${{ runner.os }}-arm64-hledger-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger-ui/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-ui/.stack-work
-        key: ${{ runner.os }}-arm64-hledger-ui-stack-work-${{ hashFiles('hledger-ui/package.yaml') }}
+        key: ${{ runner.os }}-arm64-hledger-ui-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-ui/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-arm64-hledger-ui-stack-work
+             ${{ runner.os }}-arm64-hledger-ui-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger-web/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-web/.stack-work
-        key: ${{ runner.os }}-arm64-hledger-web-stack-work-${{ hashFiles('hledger-web/package.yaml') }}
+        key: ${{ runner.os }}-arm64-hledger-web-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-web/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-arm64-hledger-web-stack-work
+             ${{ runner.os }}-arm64-hledger-web-stack-work-${{ env.ghc }}
 
     # actions:
 
diff --git a/.github/workflows/binaries-mac-x64.yml b/.github/workflows/binaries-mac-x64.yml
index a04e79472..8a2d8b3e6 100644
--- a/.github/workflows/binaries-mac-x64.yml
+++ b/.github/workflows/binaries-mac-x64.yml
@@ -34,65 +34,65 @@ jobs:
       run: |
         tools/checkembeddedfiles
 
-    # caching
+    # CACHES
 
     - name: Cache - stack-installed ~/.local/bin
       id:   stack-programs
       uses: actions/cache@v4
       with:
         path: ~/.local/bin
-        key: ${{ runner.os }}-x64-stack-programs-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-stack-programs-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-x64-stack-programs
+             ${{ runner.os }}-x64-stack-programs-${{ env.ghc }}
 
     - name: Cache - ~/.stack
       id:   stack-global
       uses: actions/cache@v4
       with:
         path: ~/.stack
-        key: ${{ runner.os }}-x64-stack-global-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-stack-global-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-x64-stack-global
+             ${{ runner.os }}-x64-stack-global-${{ env.ghc }}
 
     - name: Cache - ./.stack-work
       uses: actions/cache@v4
       with:
         path: .stack-work
-        key: ${{ runner.os }}-x64-stack-work-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-stack-work-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-x64-stack-work
+             ${{ runner.os }}-x64-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger-lib/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-lib/.stack-work
-        key: ${{ runner.os }}-x64-hledger-lib-stack-work-${{ hashFiles('hledger-lib/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-lib-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-lib/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-x64-hledger-lib-stack-work
+             ${{ runner.os }}-x64-hledger-lib-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger/.stack-work
-        key: ${{ runner.os }}-x64-hledger-stack-work-${{ hashFiles('hledger/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-stack-work-${{ env.ghc }}-${{ hashFiles('hledger/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-x64-hledger-stack-work
+             ${{ runner.os }}-x64-hledger-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger-ui/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-ui/.stack-work
-        key: ${{ runner.os }}-x64-hledger-ui-stack-work-${{ hashFiles('hledger-ui/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-ui-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-ui/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-x64-hledger-ui-stack-work
+             ${{ runner.os }}-x64-hledger-ui-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger-web/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-web/.stack-work
-        key: ${{ runner.os }}-x64-hledger-web-stack-work-${{ hashFiles('hledger-web/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-web-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-web/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-x64-hledger-web-stack-work
+             ${{ runner.os }}-x64-hledger-web-stack-work-${{ env.ghc }}
 
     # actions:
 
diff --git a/.github/workflows/binaries-windows-x64.yml b/.github/workflows/binaries-windows-x64.yml
index 62e3f15f7..76ca84c4e 100644
--- a/.github/workflows/binaries-windows-x64.yml
+++ b/.github/workflows/binaries-windows-x64.yml
@@ -30,7 +30,7 @@ jobs:
       with: 
         fetch-depth: 0
 
-    # caching
+    # CACHES
 
     # Warning: Path Validation Error: Path(s) specified in the action for caching do(es) not exist, hence no cache is being saved.
     # - name: Cache - stack programs dir   # ghc, ghc-included packages and their haddocks, mingw, msys2
@@ -40,58 +40,58 @@ jobs:
     #     path: C:\Users\runneradmin\AppData\Local\Programs\stack\
     #     # which files signal a change in stack's global db ?
     #     # **.yaml includes */package.yaml and stack.yaml* (too many), and hopefully no other changing yamls
-    #     key: ${{ runner.os }}-appdata-local-programs-stack-${{ hashFiles('**.yaml') }}
+    #     key: ${{ runner.os }}-x64-appdata-local-programs-stack-${{ hashFiles('**.yaml') }}
     #     restore-keys: |
-    #          ${{ runner.os }}-appdata-local-programs-stack
+    #          ${{ runner.os }}-x64-appdata-local-programs-stack
 
     - name: Cache - stack global dir
       id:   stack-global-package-db
       uses: actions/cache@v4
       with:
         path: C:\Users\runneradmin\AppData\Roaming\stack\
-        key: ${{ runner.os }}-appdata-roaming-stack-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-appdata-roaming-stack-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-appdata-roaming-stack
+             ${{ runner.os }}-x64-appdata-roaming-stack-${{ env.ghc }}
 
     - name: Cache - ./.stack-work
       uses: actions/cache@v4
       with:
         path: .stack-work
-        key: ${{ runner.os }}-stack-work-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-stack-work-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-stack-work
+             ${{ runner.os }}-x64-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger-lib/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-lib/.stack-work
-        key: ${{ runner.os }}-hledger-lib-stack-work-${{ hashFiles('hledger-lib/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-lib-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-lib/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-hledger-lib-stack-work
+             ${{ runner.os }}-x64-hledger-lib-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger/.stack-work
-        key: ${{ runner.os }}-hledger-stack-work-${{ hashFiles('hledger/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-stack-work-${{ env.ghc }}-${{ hashFiles('hledger/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-hledger-stack-work
+             ${{ runner.os }}-x64-hledger-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger-ui/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-ui/.stack-work
-        key: ${{ runner.os }}-hledger-ui-stack-work-${{ hashFiles('hledger-ui/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-ui-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-ui/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-hledger-ui-stack-work
+             ${{ runner.os }}-x64-hledger-ui-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger-web/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-web/.stack-work
-        key: ${{ runner.os }}-hledger-web-stack-work-${{ hashFiles('hledger-web/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-web-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-web/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-hledger-web-stack-work
+             ${{ runner.os }}-x64-hledger-web-stack-work-${{ env.ghc }}
 
     # actions
 
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fb6d7dc1d..d45c7517b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -139,9 +139,9 @@ jobs:
         # XXX if stack.yaml is a symlink, this fails with
         #  Error: The template is not valid. .github/workflows/push.yml (Line: 103, Col: 14): hashFiles('**.yaml') failed.
         #  Fail to hash files under directory '/home/runner/work/hledger/hledger'
-        key: ${{ runner.os }}-stack-global-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-stack-global-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-stack-global-${{ env.ghc }}
+             ${{ runner.os }}-x64-stack-global-${{ env.ghc }}
       if: env.do-all
 
     - name: Cache - stack-installed programs in ~/.local/bin
@@ -149,54 +149,54 @@ jobs:
       uses: actions/cache@v4
       with:
         path: ~/.local/bin
-        key: ${{ runner.os }}-stack-programs-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-stack-programs-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-stack-programs-${{ env.ghc }}
+             ${{ runner.os }}-x64-stack-programs-${{ env.ghc }}
       if: env.do-all
 
     - name: Cache - .stack-work
       uses: actions/cache@v4
       with:
         path: .stack-work
-        key: ${{ runner.os }}-stack-work-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-stack-work-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-stack-work-${{ env.ghc }}
+             ${{ runner.os }}-x64-stack-work-${{ env.ghc }}
       if: env.do-all
 
     - name: Cache - hledger-lib/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-lib/.stack-work
-        key: ${{ runner.os }}-hledger-lib-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-lib/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-lib-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-lib/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-hledger-lib-stack-work-${{ env.ghc }}
+             ${{ runner.os }}-x64-hledger-lib-stack-work-${{ env.ghc }}
       if: env.do-all
 
     - name: Cache - hledger/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger/.stack-work
-        key: ${{ runner.os }}-hledger-stack-work-${{ env.ghc }}-${{ hashFiles('hledger/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-stack-work-${{ env.ghc }}-${{ hashFiles('hledger/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-hledger-stack-work-${{ env.ghc }}
+             ${{ runner.os }}-x64-hledger-stack-work-${{ env.ghc }}
       if: env.do-all
 
     - name: Cache - hledger-ui/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-ui/.stack-work
-        key: ${{ runner.os }}-hledger-ui-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-ui/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-ui-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-ui/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-hledger-ui-stack-work-${{ env.ghc }}
+             ${{ runner.os }}-x64-hledger-ui-stack-work-${{ env.ghc }}
       if: env.do-all
 
     - name: Cache - hledger-web/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-web/.stack-work
-        key: ${{ runner.os }}-hledger-web-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-web/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-web-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-web/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-hledger-web-stack-work-${{ env.ghc }}
+             ${{ runner.os }}-x64-hledger-web-stack-work-${{ env.ghc }}
       if: env.do-all
 
     # Ensure the ghc version we need is installed.
diff --git a/.github/workflows/oldest.yml b/.github/workflows/oldest.yml
index cab7e84d9..fc26cf5d9 100644
--- a/.github/workflows/oldest.yml
+++ b/.github/workflows/oldest.yml
@@ -39,58 +39,58 @@ jobs:
         # XXX if stack.yaml is a symlink, this fails with
         #  Error: The template is not valid. .github/workflows/push.yml (Line: 103, Col: 14): hashFiles('**.yaml') failed.
         #  Fail to hash files under directory '/home/runner/work/hledger/hledger'
-        key: ${{ runner.os }}-stack-global-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-stack-global-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-stack-global-${{ env.ghc }}
+             ${{ runner.os }}-x64-stack-global-${{ env.ghc }}
 
     - name: Cache - stack-installed programs in ~/.local/bin
       id:   stack-programs
       uses: actions/cache@v4
       with:
         path: ~/.local/bin
-        key: ${{ runner.os }}-stack-programs-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-stack-programs-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-stack-programs-${{ env.ghc }}
+             ${{ runner.os }}-x64-stack-programs-${{ env.ghc }}
 
     - name: Cache - .stack-work
       uses: actions/cache@v4
       with:
         path: .stack-work
-        key: ${{ runner.os }}-stack-work-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
+        key: ${{ runner.os }}-x64-stack-work-${{ env.ghc }}-${{ hashFiles('**.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-stack-work-${{ env.ghc }}
+             ${{ runner.os }}-x64-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger-lib/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-lib/.stack-work
-        key: ${{ runner.os }}-hledger-lib-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-lib/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-lib-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-lib/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-hledger-lib-stack-work-${{ env.ghc }}
+             ${{ runner.os }}-x64-hledger-lib-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger/.stack-work
-        key: ${{ runner.os }}-hledger-stack-work-${{ env.ghc }}-${{ hashFiles('hledger/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-stack-work-${{ env.ghc }}-${{ hashFiles('hledger/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-hledger-stack-work-${{ env.ghc }}
+             ${{ runner.os }}-x64-hledger-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger-ui/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-ui/.stack-work
-        key: ${{ runner.os }}-hledger-ui-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-ui/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-ui-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-ui/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-hledger-ui-stack-work-${{ env.ghc }}
+             ${{ runner.os }}-x64-hledger-ui-stack-work-${{ env.ghc }}
 
     - name: Cache - hledger-web/.stack-work
       uses: actions/cache@v4
       with:
         path: hledger-web/.stack-work
-        key: ${{ runner.os }}-hledger-web-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-web/package.yaml') }}
+        key: ${{ runner.os }}-x64-hledger-web-stack-work-${{ env.ghc }}-${{ hashFiles('hledger-web/package.yaml') }}
         restore-keys: |
-             ${{ runner.os }}-hledger-web-stack-work-${{ env.ghc }}
+             ${{ runner.os }}-x64-hledger-web-stack-work-${{ env.ghc }}
 
 
     # ACTIONS