diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ab63d3af..70f8d1a2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -40,14 +40,13 @@ jobs:
           # operating systems
           - { os: windows-latest, rust-version: stable,  target: 'x86_64-pc-windows-msvc',   publish: true }
           - { os: macos-latest,   rust-version: stable,  target: 'x86_64-apple-darwin',      publish: true }
-          - { os: ubuntu-20.04,   rust-version: stable,  target: 'x86_64-unknown-linux-gnu', publish: true }
           # architectures
           - { os: ubuntu-22.04,   rust-version: stable,  target: 'x86_64-unknown-linux-gnu', publish: true }
           - { os: ubuntu-22.04,   rust-version: stable,  target: 'i686-unknown-linux-gnu',   publish: true }
           # FIXME(issue #2138): run wasm tests, failing to run since https://github.com/mthom/scryer-prolog/pull/2137 removed wasm-pack
           - { os: ubuntu-22.04,   rust-version: nightly, target: 'wasm32-unknown-unknown',   publish: true, args: '--no-default-features' , test-args: '--no-run --no-default-features', use_swap: true }
           # Cargo.toml rust-version
-          - { os: ubuntu-22.04,   rust-version: "1.77",  target: 'x86_64-unknown-linux-gnu'}
+          - { os: ubuntu-22.04,   rust-version: "1.85",  target: 'x86_64-unknown-linux-gnu'}
           # rust versions
           - { os: ubuntu-22.04,   rust-version: beta,    target: 'x86_64-unknown-linux-gnu'}
           - { os: ubuntu-22.04,   rust-version: nightly, target: 'x86_64-unknown-linux-gnu', miri: true, components: "miri"} 
@@ -95,13 +94,13 @@ jobs:
 
   logtalk-test:
     # if: false # uncomment to disable job
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     needs: [build-test]
     steps:
       # Download prebuilt ubuntu binary from build-test job, setup logtalk
       - uses: actions/download-artifact@v4
         with:
-          name: scryer-prolog_ubuntu-20.04_x86_64-unknown-linux-gnu
+          name: scryer-prolog_ubuntu-22.04_x86_64-unknown-linux-gnu
       - run: |
           chmod +x scryer-prolog
           echo "$PWD" >> "$GITHUB_PATH"
diff --git a/Cargo.toml b/Cargo.toml
index baf6b960..536e5793 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,7 +10,8 @@ license = "BSD-3-Clause"
 keywords = ["prolog", "prolog-interpreter", "prolog-system"]
 categories = ["command-line-utilities"]
 build = "build/main.rs"
-rust-version = "1.77"
+# Remember to check CI
+rust-version = "1.85"
 
 [lib]
 crate-type = ["cdylib", "rlib"]
diff --git a/flake.lock b/flake.lock
index c1bd6923..e7d0f27a 100644
--- a/flake.lock
+++ b/flake.lock
@@ -5,11 +5,11 @@
         "systems": "systems"
       },
       "locked": {
-        "lastModified": 1710146030,
-        "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "b1d9ab70662946ef0850d488da1c9019f3a9752a",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
         "type": "github"
       },
       "original": {
@@ -20,11 +20,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1723541349,
-        "narHash": "sha256-LrmeqqHdPgAJsVKIJja8jGgRG/CA2y6SGT2TjX5Do68=",
+        "lastModified": 1744868846,
+        "narHash": "sha256-5RJTdUHDmj12Qsv7XOhuospjAjATNiTMElplWnJE9Hs=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "4877ea239f4d02410c3516101faf35a81af0c30e",
+        "rev": "ebe4301cbd8f81c4f8d3244b3632338bbeb6d49c",
         "type": "github"
       },
       "original": {
@@ -48,11 +48,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1723515680,
-        "narHash": "sha256-nHdKymsHCVIh0Wdm4MvSgxcTTg34FJIYHRQkQYaSuvk=",
+        "lastModified": 1745289264,
+        "narHash": "sha256-7nt+UJ7qaIUe2J7BdnEEph9n2eKEwxUwKS/QIr091uA=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "4ee3d9e9569f70d7bb40f28804d6fe950c81eab3",
+        "rev": "3b7171858c20d5293360042936058fb0c4cb93a9",
         "type": "github"
       },
       "original": {