diff --git a/flake.nix b/flake.nix
index 37a7499..032b329 100644
--- a/flake.nix
+++ b/flake.nix
@@ -209,41 +209,11 @@
                 [
                   "__CHANNEL_LIST__"
                   "__VERSION_FILES__"
-                  "__READ_VERSION__"
-                  "__WRITE_VERSION__"
                   "__POST_VERSION__"
                 ]
                 [
                   channelList
                   versionFilesScript
-                  ''
-                    if [[ ! -f "$ROOT_DIR/VERSION" ]]; then
-                      echo "Error: missing $ROOT_DIR/VERSION" >&2
-                      exit 1
-                    fi
-
-                    base_line="$(sed -n '1p' "$ROOT_DIR/VERSION" | tr -d '\r')"
-                    channel_line="$(sed -n '2p' "$ROOT_DIR/VERSION" | tr -d '\r')"
-                    n_line="$(sed -n '3p' "$ROOT_DIR/VERSION" | tr -d '\r')"
-
-                    # Backward compatibility: old single-line format.
-                    if [[ -z "$channel_line" ]]; then
-                      printf '%s\n' "$base_line"
-                    elif [[ "$channel_line" == "stable" ]]; then
-                      printf '%s\n' "$base_line"
-                    else
-                      printf '%s-%s.%s\n' "$base_line" "$channel_line" "$n_line"
-                    fi
-                  ''
-                  ''
-                    channel_to_write="$CHANNEL"
-                    n_to_write="''${PRERELEASE_NUM:-1}"
-                    if [[ "$channel_to_write" == "stable" || -z "$channel_to_write" ]]; then
-                      channel_to_write="stable"
-                      n_to_write="0"
-                    fi
-                    printf '%s\n%s\n%s\n' "$BASE_VERSION" "$channel_to_write" "$n_to_write" > "$ROOT_DIR/VERSION"
-                  ''
                   postVersion
                 ]
                 (builtins.readFile ./packages/release/release.sh);
diff --git a/packages/release/release.nix b/packages/release/release.nix
index a85e0b0..44074af 100644
--- a/packages/release/release.nix
+++ b/packages/release/release.nix
@@ -30,41 +30,11 @@ let
       [
         "__CHANNEL_LIST__"
         "__VERSION_FILES__"
-        "__READ_VERSION__"
-        "__WRITE_VERSION__"
         "__POST_VERSION__"
       ]
       [
         channelList
         versionFilesScript
-        ''
-          if [[ ! -f "$ROOT_DIR/VERSION" ]]; then
-            echo "Error: missing $ROOT_DIR/VERSION" >&2
-            exit 1
-          fi
-
-          base_line="$(sed -n '1p' "$ROOT_DIR/VERSION" | tr -d '\r')"
-          channel_line="$(sed -n '2p' "$ROOT_DIR/VERSION" | tr -d '\r')"
-          n_line="$(sed -n '3p' "$ROOT_DIR/VERSION" | tr -d '\r')"
-
-          # Backward compatibility: old single-line format.
-          if [[ -z "$channel_line" ]]; then
-            printf '%s\n' "$base_line"
-          elif [[ "$channel_line" == "stable" ]]; then
-            printf '%s\n' "$base_line"
-          else
-            printf '%s-%s.%s\n' "$base_line" "$channel_line" "$n_line"
-          fi
-        ''
-        ''
-          channel_to_write="$CHANNEL"
-          n_to_write="''${PRERELEASE_NUM:-1}"
-          if [[ "$channel_to_write" == "stable" || -z "$channel_to_write" ]]; then
-            channel_to_write="stable"
-            n_to_write="0"
-          fi
-          printf '%s\n%s\n%s\n' "$BASE_VERSION" "$channel_to_write" "$n_to_write" > "$ROOT_DIR/VERSION"
-        ''
         postVersion
       ]
       (builtins.readFile ./release.sh);
diff --git a/packages/release/release.sh b/packages/release/release.sh
index bad0369..96e6ac2 100644
--- a/packages/release/release.sh
+++ b/packages/release/release.sh
@@ -192,18 +192,65 @@ generate_version_files() {
   __VERSION_FILES__
 }
 
-# ── user-provided hooks ────────────────────────────────────────────────────
+# ── version source (built-in) ──────────────────────────────────────────────
 
 do_read_version() {
-  :
-  __READ_VERSION__
+  if [[ ! -f "$ROOT_DIR/VERSION" ]]; then
+    local highest_tag=""
+    while IFS= read -r raw_tag; do
+      local tag="${raw_tag#v}"
+      [[ $tag =~ ^[0-9]+\.[0-9]+\.[0-9]+(-[a-zA-Z]+\.[0-9]+)?$ ]] || continue
+
+      if [[ -z $highest_tag ]]; then
+        highest_tag="$tag"
+        continue
+      fi
+
+      local cmp_status=0
+      version_cmp "$tag" "$highest_tag" || cmp_status=$?
+      [[ $cmp_status -eq 1 ]] && highest_tag="$tag"
+    done < <(git tag --list)
+
+    [[ -z $highest_tag ]] && highest_tag="0.0.1"
+
+    parse_full_version "$highest_tag"
+    local channel_to_write="$CHANNEL"
+    local n_to_write="${PRERELEASE_NUM:-1}"
+    if [[ $channel_to_write == "stable" || -z $channel_to_write ]]; then
+      channel_to_write="stable"
+      n_to_write="0"
+    fi
+
+    printf '%s\n%s\n%s\n' "$BASE_VERSION" "$channel_to_write" "$n_to_write" > "$ROOT_DIR/VERSION"
+    log "Initialized $ROOT_DIR/VERSION from highest tag: v$highest_tag"
+  fi
+
+  local base_line channel_line n_line
+  base_line="$(sed -n '1p' "$ROOT_DIR/VERSION" | tr -d '\r')"
+  channel_line="$(sed -n '2p' "$ROOT_DIR/VERSION" | tr -d '\r')"
+  n_line="$(sed -n '3p' "$ROOT_DIR/VERSION" | tr -d '\r')"
+
+  if [[ -z $channel_line ]]; then
+    printf '%s\n' "$base_line"
+  elif [[ $channel_line == "stable" ]]; then
+    printf '%s\n' "$base_line"
+  else
+    printf '%s-%s.%s\n' "$base_line" "$channel_line" "$n_line"
+  fi
 }
 
 do_write_version() {
-  :
-  __WRITE_VERSION__
+  local channel_to_write="$CHANNEL"
+  local n_to_write="${PRERELEASE_NUM:-1}"
+  if [[ $channel_to_write == "stable" || -z $channel_to_write ]]; then
+    channel_to_write="stable"
+    n_to_write="0"
+  fi
+  printf '%s\n%s\n%s\n' "$BASE_VERSION" "$channel_to_write" "$n_to_write" > "$ROOT_DIR/VERSION"
 }
 
+# ── user-provided hook ─────────────────────────────────────────────────────
+
 do_post_version() {
   :
   __POST_VERSION__