diff --git a/pkgs/development/compilers/crystal/default.nix b/pkgs/development/compilers/crystal/default.nix
index 4d85f7b815c3..367a08aa87cb 100644
--- a/pkgs/development/compilers/crystal/default.nix
+++ b/pkgs/development/compilers/crystal/default.nix
@@ -16,7 +16,6 @@
   libxml2,
   libyaml,
   libffi,
-  llvmPackages_15,
   llvmPackages_19,
   llvmPackages_20,
   llvmPackages_21,
@@ -170,11 +169,7 @@ let
         export threads=$NIX_BUILD_CORES
         export CRYSTAL_CACHE_DIR=$TMP
         export MACOSX_DEPLOYMENT_TARGET=10.11
-
-        # Available since 1.13.0 https://github.com/crystal-lang/crystal/pull/14574
-        if [[ -f src/SOURCE_DATE_EPOCH ]]; then
-          export SOURCE_DATE_EPOCH="$(<src/SOURCE_DATE_EPOCH)"
-        fi
+        export SOURCE_DATE_EPOCH="$(<src/SOURCE_DATE_EPOCH)"
       '';
 
       strictDeps = true;
@@ -298,14 +293,6 @@ rec {
     };
   };
 
-  # When removing this version, also remove checks for src/SOURCE_DATE_EPOCH existence
-  crystal_1_11 = generic {
-    version = "1.11.2";
-    sha256 = "sha256-BBEDWqFtmFUNj0kuGBzv71YHO3KjxV4d2ySTCD4HhLc=";
-    binary = binaryCrystal_1_10;
-    llvmPackages = llvmPackages_15;
-  };
-
   crystal_1_14 = generic {
     version = "1.14.1";
     sha256 = "sha256-cQWK92BfksOW8GmoXn4BmPGJ7CLyLAeKccOffQMh5UU=";
diff --git a/pkgs/top-level/aliases.nix b/pkgs/top-level/aliases.nix
index 217b22bcb254..790d34557566 100644
--- a/pkgs/top-level/aliases.nix
+++ b/pkgs/top-level/aliases.nix
@@ -652,6 +652,7 @@ mapAliases {
   crystal_1_7 = throw "'crystal_1_7' has been removed as it is obsolete and no longer used in the tree. Consider using 'crystal' instead"; # Added 2025-02-13
   crystal_1_8 = throw "'crystal_1_8' has been removed as it is obsolete and no longer used in the tree. Consider using 'crystal' instead"; # Added 2025-02-13
   crystal_1_9 = throw "'crystal_1_9' has been removed as it is obsolete and no longer used in the tree. Consider using 'crystal' instead"; # Added 2025-02-13
+  crystal_1_11 = throw "'crystal_1_11' has been removed as it is obsolete and no longer used in the tree. Consider using 'crystal' instead"; # Added 2025-09-04
   crystal_1_12 = throw "'crystal_1_12' has been removed as it is obsolete and no longer used in the tree. Consider using 'crystal' instead"; # Added 2025-02-19
   clash-geoip = throw "'clash-geoip' has been removed. Consider using 'dbip-country-lite' instead."; # added 2024-10-19
   clash-verge = throw "'clash-verge' has been removed, as it was broken and unmaintained. Consider using 'clash-verge-rev' or 'clash-nyanpasu' instead"; # Added 2024-09-17
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 49ce7b0dea97..56cf0a515911 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -4720,7 +4720,6 @@ with pkgs;
   corretto21 = javaPackages.compiler.corretto21;
 
   inherit (callPackage ../development/compilers/crystal { })
-    crystal_1_11
     crystal_1_14
     crystal_1_15
     crystal_1_16