diff --git a/apps/readest-app/src/utils/book.ts b/apps/readest-app/src/utils/book.ts
index 9a8c70bf..2ff372e5 100644
--- a/apps/readest-app/src/utils/book.ts
+++ b/apps/readest-app/src/utils/book.ts
@@ -251,10 +251,30 @@ const normalizeIdentifier = (identifier: string) => {
   return identifier;
 };
 
+const getPreferredIdentifier = (identifiers: string[] | Identifier[]) => {
+  for (const scheme of ['uuid', 'calibre', 'isbn']) {
+    const found = identifiers.find((identifier) =>
+      typeof identifier === 'string'
+        ? identifier.toLowerCase().includes(scheme)
+        : identifier.scheme.toLowerCase() === scheme,
+    );
+    if (found) {
+      return typeof found === 'string' ? normalizeIdentifier(found) : found.value;
+    }
+  }
+  return;
+};
+
 const getIdentifiersList = (
   identifiers: undefined | string | string[] | Identifier | Identifier[],
 ) => {
   if (!identifiers) return [];
+  if (Array.isArray(identifiers)) {
+    const preferred = getPreferredIdentifier(identifiers);
+    if (preferred) {
+      return [preferred];
+    }
+  }
   return Array.isArray(identifiers)
     ? identifiers
         .map((identifier) =>
@@ -267,10 +287,15 @@ const getIdentifiersList = (
 };
 
 export const getMetadataHash = (metadata: BookMetadata) => {
-  const title = getTitleForHash(metadata.title);
-  const authors = getAuthorsList(metadata.author).join(',');
-  const identifiers = getIdentifiersList(metadata.altIdentifier || metadata.identifier).join(',');
-  const hashSource = `${title}|${authors}|${identifiers}`;
-  const metaHash = md5(hashSource.normalize('NFC'));
-  return metaHash;
+  try {
+    const title = getTitleForHash(metadata.title);
+    const authors = getAuthorsList(metadata.author).join(',');
+    const identifiers = getIdentifiersList(metadata.altIdentifier || metadata.identifier).join(',');
+    const hashSource = `${title}|${authors}|${identifiers}`;
+    const metaHash = md5(hashSource.normalize('NFC'));
+    return metaHash;
+  } catch (error) {
+    console.error('Error generating metadata hash:', error);
+  }
+  return;
 };
diff --git a/apps/readest.koplugin/main.lua b/apps/readest.koplugin/main.lua
index f90b1918..924c093a 100644
--- a/apps/readest.koplugin/main.lua
+++ b/apps/readest.koplugin/main.lua
@@ -312,11 +312,25 @@ function ReadestSync:generateMetadataHash()
 
     local identifiers = doc_props.identifiers or ''
     if identifiers:find("\n") then
-        identifiers = util.splitToArray(identifiers, "\n")
-        for i, id in ipairs(identifiers) do
-            identifiers[i] = normalizeIdentifier(id)
+        local list = util.splitToArray(identifiers, "\n")
+        local normalized = {}
+        local priorities = { "uuid", "calibre", "isbn" }
+        local preferred = nil
+        for i, id in ipairs(list) do
+            normalized[i] = normalizeIdentifier(id)
+            local candidate = id:lower()
+            for _, p in ipairs(priorities) do
+                if candidate:find(p, 1, true) then
+                    preferred = normalized[i]
+                    break
+                end
+            end
+        end
+        if preferred then
+            identifiers = preferred
+        else
+            identifiers = table.concat(normalized, ",")
         end
-        identifiers = table.concat(identifiers, ",")
     else
         identifiers = normalizeIdentifier(identifiers)
     end
@@ -327,10 +341,10 @@ end
 
 function ReadestSync:getMetaHash()
     local doc_readest_sync = self.ui.doc_settings:readSetting("readest_sync") or {}
-    local meta_hash = doc_readest_sync.meta_hash
+    local meta_hash = doc_readest_sync.meta_hash_v1
     if not meta_hash then
         meta_hash = self:generateMetadataHash()
-        doc_readest_sync.meta_hash = meta_hash
+        doc_readest_sync.meta_hash_v1 = meta_hash
         self.ui.doc_settings:saveSetting("readest_sync", doc_readest_sync)
     end
     return meta_hash