Running nixpkgs-update (https://nix-community.org/update-bot/) with UPDATE_INFO: factorio 0 -> 1
attrpath: factorio
Checking auto update branch...
[version] 
[version] generic version rewriter does not support multiple hashes
[rustCrateVersion] 
[rustCrateVersion] No cargoHash found
[golangModuleVersion] 
[golangModuleVersion] Not a buildGoModule package with vendorHash
[npmDepsVersion] 
[npmDepsVersion] No npmDepsHash
[updateScript] 
[updateScript] Success
[updateScript] 
Going to be running update for following packages:
 - factorio-alpha-2.0.77

Press Enter key to continue...
Running update for:
Enqueuing group of 1 packages
 - factorio-alpha-2.0.77: UPDATING ...
 - factorio-alpha-2.0.77: DONE.

Packages updated!

Diff after rewrites:
diff --git a/pkgs/by-name/fa/factorio/versions.json b/pkgs/by-name/fa/factorio/versions.json
index 8019aafa56ae..433f95f12899 100644
--- a/pkgs/by-name/fa/factorio/versions.json
+++ b/pkgs/by-name/fa/factorio/versions.json
@@ -3,44 +3,44 @@
     "alpha": {
       "experimental": {
         "candidateHashFilenames": [
-          "factorio_linux-arm64_2.1.20.tar.xz",
-          "factorio_linux-arm64_2.1.20.tar.xz"
+          "factorio_linux-arm64_2.1.21.tar.xz",
+          "factorio_linux-arm64_2.1.21.tar.xz"
         ],
-        "name": "factorio_alpha_arm64-2.1.20.tar.xz",
+        "name": "factorio_alpha_arm64-2.1.21.tar.xz",
         "needsAuth": true,
-        "sha256": "78420b2a8347ab1d9840c63d8dea439d191617d7748bb5562323faef484715fc",
+        "sha256": "264044a4a42eb9a993ebfcc73f905812d35158632370fefc52c4a1a1a955aa5f",
         "tarDirectory": "arm64",
-        "url": "https://factorio.com/get-download/2.1.20/alpha/linux-arm64",
-        "version": "2.1.20"
+        "url": "https://factorio.com/get-download/2.1.21/alpha/linux-arm64",
+        "version": "2.1.21"
       }
     },
     "expansion": {
       "experimental": {
         "candidateHashFilenames": [
-          "factorio-space-age_linux-arm64_2.1.20.tar.xz",
-          "factorio-space-age_linux-arm64_2.1.20.tar.xz"
+          "factorio-space-age_linux-arm64_2.1.21.tar.xz",
+          "factorio-space-age_linux-arm64_2.1.21.tar.xz"
         ],
-        "name": "factorio_expansion_arm64-2.1.20.tar.xz",
+        "name": "factorio_expansion_arm64-2.1.21.tar.xz",
         "needsAuth": true,
-        "sha256": "373417bab9ac51cdedfc88307ae9562ae0d27a3cb29bb5aa748945169e5a8a76",
+        "sha256": "49c6e25a2e6e91351d47115ec1f10a52b761323bec42461642feb151efca4628",
         "tarDirectory": "arm64",
-        "url": "https://factorio.com/get-download/2.1.20/expansion/linux-arm64",
-        "version": "2.1.20"
+        "url": "https://factorio.com/get-download/2.1.21/expansion/linux-arm64",
+        "version": "2.1.21"
       }
     },
     "headless": {
       "experimental": {
         "candidateHashFilenames": [
-          "factorio-headless_linux-arm64_2.1.20.tar.xz",
-          "factorio-headless_linux-arm64_2.1.20.tar.xz",
-          "factorio_headless_arm64_2.1.20.tar.xz"
+          "factorio-headless_linux-arm64_2.1.21.tar.xz",
+          "factorio-headless_linux-arm64_2.1.21.tar.xz",
+          "factorio_headless_arm64_2.1.21.tar.xz"
         ],
-        "name": "factorio_headless_arm64-2.1.20.tar.xz",
+        "name": "factorio_headless_arm64-2.1.21.tar.xz",
         "needsAuth": false,
-        "sha256": "6543968b416129f7ce905714e649bf7ae7b63e9eb2a01de53687ce1adf58d517",
+        "sha256": "8ded7ed5a0eac128b686df6383815401852ff4402249daf43bc9885d38b93be7",
         "tarDirectory": "arm64",
-        "url": "https://factorio.com/get-download/2.1.20/headless/linux-arm64",
-        "version": "2.1.20"
+        "url": "https://factorio.com/get-download/2.1.21/headless/linux-arm64",
+        "version": "2.1.21"
       }
     }
   },
@@ -48,15 +48,15 @@
     "alpha": {
       "experimental": {
         "candidateHashFilenames": [
-          "factorio_linux64_2.1.20.tar.xz",
-          "factorio_linux_2.1.20.tar.xz"
+          "factorio_linux64_2.1.21.tar.xz",
+          "factorio_linux_2.1.21.tar.xz"
         ],
-        "name": "factorio_alpha_x64-2.1.20.tar.xz",
+        "name": "factorio_alpha_x64-2.1.21.tar.xz",
         "needsAuth": true,
-        "sha256": "cb50311886b4e4218d1bdf9afe18b2b0298696f2a2b3711494676ac1fc77242a",
+        "sha256": "795252971d6fd33d2160721c3c2f678640cd08216bb5e11ce5244a32bc0d8be8",
         "tarDirectory": "x64",
-        "url": "https://factorio.com/get-download/2.1.20/alpha/linux64",
-        "version": "2.1.20"
+        "url": "https://factorio.com/get-download/2.1.21/alpha/linux64",
+        "version": "2.1.21"
       },
       "stable": {
         "candidateHashFilenames": [
@@ -100,15 +100,15 @@
     "expansion": {
       "experimental": {
         "candidateHashFilenames": [
-          "factorio-space-age_linux64_2.1.20.tar.xz",
-          "factorio-space-age_linux_2.1.20.tar.xz"
+          "factorio-space-age_linux64_2.1.21.tar.xz",
+          "factorio-space-age_linux_2.1.21.tar.xz"
         ],
-        "name": "factorio_expansion_x64-2.1.20.tar.xz",
+        "name": "factorio_expansion_x64-2.1.21.tar.xz",
         "needsAuth": true,
-        "sha256": "eaf3cd9a3274a6e6ea0d44840f02403440ab039b70dd37d5717e6a988ce0a08d",
+        "sha256": "3289ecfbea0852e1a398a0984fbe3ed6abbd6437af6e83edf0f9fe28735b4571",
         "tarDirectory": "x64",
-        "url": "https://factorio.com/get-download/2.1.20/expansion/linux64",
-        "version": "2.1.20"
+        "url": "https://factorio.com/get-download/2.1.21/expansion/linux64",
+        "version": "2.1.21"
       },
       "stable": {
         "candidateHashFilenames": [
@@ -126,16 +126,16 @@
     "headless": {
       "experimental": {
         "candidateHashFilenames": [
-          "factorio-headless_linux64_2.1.20.tar.xz",
-          "factorio-headless_linux_2.1.20.tar.xz",
-          "factorio_headless_x64_2.1.20.tar.xz"
+          "factorio-headless_linux64_2.1.21.tar.xz",
+          "factorio-headless_linux_2.1.21.tar.xz",
+          "factorio_headless_x64_2.1.21.tar.xz"
         ],
-        "name": "factorio_headless_x64-2.1.20.tar.xz",
+        "name": "factorio_headless_x64-2.1.21.tar.xz",
         "needsAuth": false,
-        "sha256": "421a483dbcf69b76d854b7fdb86a800c94da04e414c20803c9fce82fc191bbb5",
+        "sha256": "ff634a91048841483f5c000c070447999cc860d61b552d3f82b612c8a87372d8",
         "tarDirectory": "x64",
-        "url": "https://factorio.com/get-download/2.1.20/headless/linux64",
-        "version": "2.1.20"
+        "url": "https://factorio.com/get-download/2.1.21/headless/linux64",
+        "version": "2.1.21"
       },
       "stable": {
         "candidateHashFilenames": [

Package version did not change.