diff --git a/UnitTestProject1/Tests/PageTests.cs b/UnitTestProject1/Tests/PageTests.cs
index a4ffde480..8dd5c09d9 100644
--- a/UnitTestProject1/Tests/PageTests.cs
+++ b/UnitTestProject1/Tests/PageTests.cs
@@ -224,7 +224,7 @@ public async Task WpLzhPageLanguageLinksTest()
         public async Task WpLzhFetchRevisionsTest()
         {
             var site = await WpLzhSiteAsync;
-            var revIds = new[] { 248199, 248197, 255289 };
+            var revIds = new[] { 248199L, 248197, 255289 };
             var pageTitles = new[] { "清", "清", "香草" };
             var rev = await Revision.FetchRevisionsAsync(site, revIds).ToListAsync();
             ShallowTrace(rev);
diff --git a/WikiClientLibrary.Wikia/Discussions/Board.cs b/WikiClientLibrary.Wikia/Discussions/Board.cs
index 560402cb2..5d4412e5e 100644
--- a/WikiClientLibrary.Wikia/Discussions/Board.cs
+++ b/WikiClientLibrary.Wikia/Discussions/Board.cs
@@ -43,7 +43,7 @@ public Board(WikiaSite site, string title, int defaultNamespaceId)
         /// <param name="site">The Wikia site.</param>
         /// <param name="pageId">Page ID of the board.</param>
         /// <exception cref="ArgumentNullException"><paramref name="site"/> is <c>null</c>.</exception>
-        public Board(WikiaSite site, int pageId)
+        public Board(WikiaSite site, long pageId)
         {
             Site = site ?? throw new ArgumentNullException(nameof(site));
             Page = new WikiPageStub(pageId);
diff --git a/WikiClientLibrary.Wikia/Discussions/Post.cs b/WikiClientLibrary.Wikia/Discussions/Post.cs
index a07f6241d..ed584ec25 100644
--- a/WikiClientLibrary.Wikia/Discussions/Post.cs
+++ b/WikiClientLibrary.Wikia/Discussions/Post.cs
@@ -35,7 +35,7 @@ public class Post
         /// For now, it is not possible to get the replies by using the constructor provided here.
         /// To achieve this, you need to invoke <see cref="Board.EnumPostsAsync()"/> on a <see cref="Board"/> instance.
         /// </remarks>
-        public Post(WikiaSite site, WikiPageStub ownerPage, int id)
+        public Post(WikiaSite site, WikiPageStub ownerPage, long id)
         {
             if (ownerPage.IsEmpty) throw new ArgumentException("ownerPage is empty.", nameof(ownerPage));
             Site = site ?? throw new ArgumentNullException(nameof(site));
@@ -47,7 +47,7 @@ public Post(WikiaSite site, WikiPageStub ownerPage, int id)
         public WikiaSite Site { get; }
 
         /// <summary>Gets the ID of the post.</summary>
-        public int Id { get; private set; }
+        public long Id { get; private set; }
 
         /// <summary>Gets the stub of the page that owns the comment.</summary>
         public WikiPageStub OwnerPage { get; private set; }
diff --git a/WikiClientLibrary.Wikia/RequestHelper.cs b/WikiClientLibrary.Wikia/RequestHelper.cs
index 3ef957cb2..90aff9639 100644
--- a/WikiClientLibrary.Wikia/RequestHelper.cs
+++ b/WikiClientLibrary.Wikia/RequestHelper.cs
@@ -131,19 +131,19 @@ public static async Task RefreshPostsAsync(IEnumerable<Post> posts,
                         var pages = partition.Select(p => new WikiPage(site, p.Id)).ToList();
                         var lastRevisionTask = pages.RefreshAsync(postLastRevisionQueryProvider, cancellationToken);
                         // Fetch the first revisions, when needed, to determine author.
-                        Dictionary<int, Revision> firstRevisionDict = null;
+                        Dictionary<long, Revision> firstRevisionDict = null;
                         if (partition.Count == 1
                             || (options & PostQueryOptions.ExactAuthoringInformation) == PostQueryOptions.ExactAuthoringInformation)
                         {
                             // We can only fetch for 1 page at a time, with rvdir = "newer"
-                            firstRevisionDict = new Dictionary<int, Revision>();
+                            firstRevisionDict = new Dictionary<long, Revision>();
                             foreach (var post in partition)
                             {
                                 var generator = new RevisionsGenerator(site, post.Id)
                                 {
                                     TimeAscending = true,
                                     PaginationSize = 1,
-                                    PropertyProvider = postRevisionWithContentProvider
+                                    PropertyProvider = postRevisionWithContentProvider,
                                 };
                                 var rev = await generator.EnumItemsAsync().FirstAsync(cancellationToken);
                                 firstRevisionDict[post.Id] = rev;
@@ -163,7 +163,7 @@ public static async Task RefreshPostsAsync(IEnumerable<Post> posts,
             }
         }
 
-        public static async Task<Post> PostCommentAsync(WikiaSite site, object scopeInst, WikiPageStub owner, int? parentId, string content, CancellationToken cancellationToken)
+        public static async Task<Post> PostCommentAsync(WikiaSite site, object scopeInst, WikiPageStub owner, long? parentId, string content, CancellationToken cancellationToken)
         {
             Debug.Assert(site != null);
             Debug.Assert(owner.HasTitle);
@@ -267,7 +267,7 @@ public static async Task<Post> PostWallMessageAsync(WikiaSite site, object scope
         }
 
         public static async Task<Post> ReplyWallMessageAsync(WikiaSite site, object scopeInst, WikiPageStub owner,
-            int parentId, string messageBody, CancellationToken cancellationToken)
+            long parentId, string messageBody, CancellationToken cancellationToken)
         {
             Debug.Assert(site != null);
             using (site.BeginActionScope(scopeInst, owner, parentId))
diff --git a/WikiClientLibrary.Wikia/WikiaApi/WikiaSiteWikiaApiExtensions.cs b/WikiClientLibrary.Wikia/WikiaApi/WikiaSiteWikiaApiExtensions.cs
index 5120d58fb..e23dfce42 100644
--- a/WikiClientLibrary.Wikia/WikiaApi/WikiaSiteWikiaApiExtensions.cs
+++ b/WikiClientLibrary.Wikia/WikiaApi/WikiaSiteWikiaApiExtensions.cs
@@ -106,15 +106,15 @@ public static async IAsyncEnumerable<UserInfo> FetchUsersAsync(this WikiaSite si
             }
         }
 
-        /// <inheritdoc cref="FetchRelatedPagesAsync(WikiaSite,int,int,CancellationToken)"/>
+        /// <inheritdoc cref="FetchRelatedPagesAsync(WikiaSite,long,int,CancellationToken)"/>
         /// <remarks>This overload fetches 10 items at most.</remarks>
-        public static Task<IList<RelatedPageItem>> FetchRelatedPagesAsync(this WikiaSite site, int pageId)
+        public static Task<IList<RelatedPageItem>> FetchRelatedPagesAsync(this WikiaSite site, long pageId)
         {
             return FetchRelatedPagesAsync(site, pageId, 10, CancellationToken.None);
         }
 
-        /// <inheritdoc cref="FetchRelatedPagesAsync(WikiaSite,int,int,CancellationToken)"/>
-        public static Task<IList<RelatedPageItem>> FetchRelatedPagesAsync(this WikiaSite site, int pageId, int maxCount)
+        /// <inheritdoc cref="FetchRelatedPagesAsync(WikiaSite,long,int,CancellationToken)"/>
+        public static Task<IList<RelatedPageItem>> FetchRelatedPagesAsync(this WikiaSite site, long pageId, int maxCount)
         {
             return FetchRelatedPagesAsync(site, pageId, maxCount, CancellationToken.None);
         }
@@ -131,7 +131,7 @@ public static Task<IList<RelatedPageItem>> FetchRelatedPagesAsync(this WikiaSite
         /// <exception cref="NotFoundApiException"><c>Related Pages</c> extension is not available.</exception>
         /// <returns></returns>
         public static async Task<IList<RelatedPageItem>> FetchRelatedPagesAsync(this WikiaSite site,
-            int pageId, int maxCount, CancellationToken cancellationToken)
+            long pageId, int maxCount, CancellationToken cancellationToken)
         {
             if (site == null) throw new ArgumentNullException(nameof(site));
             if (maxCount <= 0) throw new ArgumentOutOfRangeException(nameof(maxCount));
diff --git a/WikiClientLibrary.Wikibase/Entity.cs b/WikiClientLibrary.Wikibase/Entity.cs
index 84d2d16c1..e0f3d87f9 100644
--- a/WikiClientLibrary.Wikibase/Entity.cs
+++ b/WikiClientLibrary.Wikibase/Entity.cs
@@ -124,7 +124,7 @@ public Entity(WikiSite site, string id)
         /// The property value is invalidated after you have performed edits on this instance.
         /// To fetch the latest value, use <see cref="RefreshAsync(EntityQueryOptions)"/>.
         /// </remarks>
-        public int PageId { get; private set; }
+        public long PageId { get; private set; }
 
         /// <summary>
         /// Namespace ID of the entity page.
@@ -164,7 +164,7 @@ public Entity(WikiSite site, string id)
         /// <summary>
         /// The revid of the last revision.
         /// </summary>
-        public int LastRevisionId { get; private set; }
+        public long LastRevisionId { get; private set; }
 
         /// <inheritdoc />
         public WbMonolingualTextCollection Labels { get; private set; } = emptyStringDict;
@@ -268,12 +268,12 @@ internal void LoadFromContract(Contracts.Entity entity, EntityQueryOptions optio
                 if (!isPostEditing)
                 {
                     // wbeditentity response does not have these properties.
-                    PageId = (int)extensionData["pageid"];
+                    PageId = (long)extensionData["pageid"];
                     NamespaceId = (int)extensionData["ns"];
                     Title = (string)extensionData["title"];
                     LastModified = (DateTime)extensionData["modified"];
                 }
-                LastRevisionId = (int)extensionData["lastrevid"];
+                LastRevisionId = (long)extensionData["lastrevid"];
             }
 
             Labels = (options & EntityQueryOptions.FetchLabels) == EntityQueryOptions.FetchLabels && serializable.Labels.Count > 0
diff --git a/WikiClientLibrary/Generators/LogEventsList.cs b/WikiClientLibrary/Generators/LogEventsList.cs
index 4a883cfa2..cb241c734 100644
--- a/WikiClientLibrary/Generators/LogEventsList.cs
+++ b/WikiClientLibrary/Generators/LogEventsList.cs
@@ -217,7 +217,7 @@ internal static LogEventItem FromRecentChangeItem(RecentChangeItem rc)
         
         /// <summary>the page id at the time the log was stored.</summary>
         [JsonProperty("logpage")]
-        public int PageId { get; private set; }
+        public long PageId { get; private set; }
 
         /// <summary>Name of the user making this recent change.</summary>
         [JsonProperty("user")]
@@ -229,13 +229,13 @@ internal static LogEventItem FromRecentChangeItem(RecentChangeItem rc)
         /// for account creation events, this is user ID of the creating user is returned.
         /// When absent, this is the user ID returned is that of the created account
         /// (see <a href="https://phabricator.wikimedia.org/T73020">phab:T73020</a>).
-        /// In most cases (such as in <see cref="LogEventsList"/> or <see cref="RecentChangesGenerator"/>,
+        /// In most cases (such as in <see cref="LogEventsList"/> or <see cref="RecentChangesGenerator"/>),
         /// <c>userid</c> property is specified implicitly.</para>
         /// <para>To get the user ID for the created user, especially in <see cref="LogActions.Create2"/> log action,
         /// use <see cref="Params"/>.<see cref="LogParameterCollection.UserId"/> .</para>
         /// </remarks>
         [JsonProperty]
-        public int UserId { get; private set; }
+        public long UserId { get; private set; }
 
         /// <summary>The time and date of the change.</summary>
         [JsonProperty]
@@ -404,12 +404,12 @@ static LogParameterCollection()
         /// <summary>
         /// (<see cref="LogActions.Patrol"/>)
         /// </summary>
-        public int CurrentRevisionId => GetInt32Value("curid", 0);
+        public long CurrentRevisionId => GetInt64Value("curid", 0);
 
         /// <summary>
         /// (<see cref="LogActions.Patrol"/>)
         /// </summary>
-        public int PreviousRevisionId => GetInt32Value("previd", 0);
+        public long PreviousRevisionId => GetInt64Value("previd", 0);
 
         /// <summary>
         /// (<see cref="LogActions.Patrol"/>)
@@ -420,7 +420,7 @@ static LogParameterCollection()
         /// (<see cref="LogTypes.NewUsers"/>) The user ID of the created user.
         /// </summary>
         /// <see cref="LogEventItem.UserId"/>
-        public int UserId => GetInt32Value("userid", 0);
+        public long UserId => GetInt64Value("userid", 0);
 
     }
 
diff --git a/WikiClientLibrary/Generators/Primitive/WikiPagePropertyList.cs b/WikiClientLibrary/Generators/Primitive/WikiPagePropertyList.cs
index ed73e455c..c73507b9c 100644
--- a/WikiClientLibrary/Generators/Primitive/WikiPagePropertyList.cs
+++ b/WikiClientLibrary/Generators/Primitive/WikiPagePropertyList.cs
@@ -61,8 +61,8 @@ protected WikiPagePropertyList(WikiSite site, WikiPageStub pageStub)
         /// Gets/sets the page ID from which to get the <c>list</c>-like property value.
         /// </summary>
         /// <remarks>If <see cref="PageTitle"/> is <c>null</c>, the value of this property will be used.
-        /// Otherwise the other one will be effective.</remarks>
-        public int PageId { get; set; }
+        /// Otherwise, the other one will be effective.</remarks>
+        public long PageId { get; set; }
 
         /// <summary>
         /// Gets/sets maximum items returned per MediaWiki API invocation.
diff --git a/WikiClientLibrary/Generators/RecentChangeItem.cs b/WikiClientLibrary/Generators/RecentChangeItem.cs
index cc895693a..c5051b96d 100644
--- a/WikiClientLibrary/Generators/RecentChangeItem.cs
+++ b/WikiClientLibrary/Generators/RecentChangeItem.cs
@@ -78,19 +78,19 @@ private string TypeName
 
         /// <summary>ID of the page affected by this item.</summary>
         [JsonProperty]
-        public int PageId { get; private set; }
+        public long PageId { get; private set; }
 
         /// <summary>ID of the new revision affected by this item.</summary>
         [JsonProperty("revid")]
-        public int RevisionId { get; private set; }
+        public long RevisionId { get; private set; }
 
         /// <summary>ID of the old revision affected by this item.</summary>
         [JsonProperty("old_revid")]
-        public int OldRevisionId { get; private set; }
+        public long OldRevisionId { get; private set; }
 
         /// <summary>ID of recent change entry.</summary>
         [JsonProperty("rcid")]
-        public int Id { get; private set; }
+        public long Id { get; private set; }
 
         /// <summary>Name of the user making this recent change.</summary>
         [JsonProperty("user")]
@@ -100,7 +100,7 @@ private string TypeName
         /// <remarks>When using this property with log events, there are some caveats.
         /// See <see cref="LogEventItem.UserId"/> for more information.</remarks>
         [JsonProperty]
-        public int UserId { get; private set; }
+        public long UserId { get; private set; }
 
         /// <summary>Content length of the old revision affected by this item.</summary>
         [JsonProperty("oldlen")]
diff --git a/WikiClientLibrary/Generators/RevisionsGenerator.cs b/WikiClientLibrary/Generators/RevisionsGenerator.cs
index 8b1a1c8ff..a91dd85ac 100644
--- a/WikiClientLibrary/Generators/RevisionsGenerator.cs
+++ b/WikiClientLibrary/Generators/RevisionsGenerator.cs
@@ -92,12 +92,12 @@ protected override Revision ItemFromJson(JToken json, JObject jpage)
         /// <summary>
         /// Revision ID to start listing from.
         /// </summary>
-        public int? StartRevisionId { get; set; }
+        public long? StartRevisionId { get; set; }
 
         /// <summary>
         /// Revision ID to stop listing at. 
         /// </summary>
-        public int? EndRevisionId { get; set; }
+        public long? EndRevisionId { get; set; }
 
         /// <summary>
         /// Only list revisions made by this user.
diff --git a/WikiClientLibrary/Infrastructures/WikiReadOnlyDictionary.cs b/WikiClientLibrary/Infrastructures/WikiReadOnlyDictionary.cs
index 0e0009dc5..10eb54735 100644
--- a/WikiClientLibrary/Infrastructures/WikiReadOnlyDictionary.cs
+++ b/WikiClientLibrary/Infrastructures/WikiReadOnlyDictionary.cs
@@ -58,29 +58,51 @@ public JToken this[string key]
             return null;
         }
 
+        /// <inheritdoc cref="GetInt64Value(string)"/>
         /// <summary>
         /// Gets the <see cref="int"/> value by property name.
         /// This overload raises exception for missing key.
         /// </summary>
+        /// <see cref="GetInt64Value(string,long)"/>
+        public int GetInt32Value(string key)
+        {
+            return (int)myDict[key];
+        }
+
+        /// <inheritdoc cref="GetInt64Value(string,long)"/>
+        /// <summary>
+        /// Gets the <see cref="int"/> value by property name.
+        /// A default value can be provided in case the specified key does not exist.
+        /// </summary>
+        public int GetInt32Value(string key, int defaultValue)
+        {
+            if (myDict.TryGetValue(key, out var value)) return (int)value;
+            return defaultValue;
+        }
+
+        /// <summary>
+        /// Gets the <see cref="long"/> value by property name.
+        /// This overload raises exception for missing key.
+        /// </summary>
         /// <param name="key">The property name.</param>
         /// <returns>The converted value.</returns>
         /// <exception cref="KeyNotFoundException">The property is not found.</exception>
         /// <see cref="GetInt32Value(string,int)"/>
-        public int GetInt32Value(string key)
+        public long GetInt64Value(string key)
         {
-            return (int)myDict[key];
+            return (long)myDict[key];
         }
 
         /// <summary>
-        /// Gets the <see cref="int"/> value by property name.
+        /// Gets the <see cref="long"/> value by property name.
         /// A default value can be provided in case the specified key does not exist.
         /// </summary>
         /// <param name="key">The property name.</param>
         /// <param name="defaultValue">The default value.</param>
         /// <returns>The converted value - or - <paramref name="defaultValue"/>.</returns>
-        public int GetInt32Value(string key, int defaultValue)
+        public long GetInt64Value(string key, long defaultValue)
         {
-            if (myDict.TryGetValue(key, out var value)) return (int)value;
+            if (myDict.TryGetValue(key, out var value)) return (long)value;
             return defaultValue;
         }
 
diff --git a/WikiClientLibrary/Pages/Parsing/ParsedContentInfo.cs b/WikiClientLibrary/Pages/Parsing/ParsedContentInfo.cs
index 6a7fd9e73..d6bb61474 100644
--- a/WikiClientLibrary/Pages/Parsing/ParsedContentInfo.cs
+++ b/WikiClientLibrary/Pages/Parsing/ParsedContentInfo.cs
@@ -36,10 +36,10 @@ public ParsedContentInfo()
         public string DisplayTitle { get; private set; }
 
         [JsonProperty]
-        public int PageId { get; private set; }
+        public long PageId { get; private set; }
 
         [JsonProperty("revid")]
-        public int RevisionId { get; private set; }
+        public long RevisionId { get; private set; }
 
         /// <summary>
         /// Parsed content, in HTML form.
diff --git a/WikiClientLibrary/Pages/Queries/Properties/PageInfoPropertyProvider.cs b/WikiClientLibrary/Pages/Queries/Properties/PageInfoPropertyProvider.cs
index eae481206..faa2a3473 100644
--- a/WikiClientLibrary/Pages/Queries/Properties/PageInfoPropertyProvider.cs
+++ b/WikiClientLibrary/Pages/Queries/Properties/PageInfoPropertyProvider.cs
@@ -69,7 +69,7 @@ protected internal PageInfoPropertyGroup(JObject jPage)
 
         public DateTime LastTouched { get; }
 
-        public int LastRevisionId { get; }
+        public long LastRevisionId { get; }
 
         public int ContentLength { get; }
 
diff --git a/WikiClientLibrary/Pages/Revision.cs b/WikiClientLibrary/Pages/Revision.cs
index 6c52824f3..014a84a86 100644
--- a/WikiClientLibrary/Pages/Revision.cs
+++ b/WikiClientLibrary/Pages/Revision.cs
@@ -34,31 +34,31 @@ public class Revision
         /// share the same reference.</para>
         /// </remarks>
         /// <exception cref="ArgumentException"><paramref name="revisionId"/> is not an existing revision id.</exception>
-        public static ValueTask<Revision> FetchRevisionAsync(WikiSite site, int revisionId)
+        public static ValueTask<Revision> FetchRevisionAsync(WikiSite site, long revisionId)
         {
             return FetchRevisionsAsync(site, new[] { revisionId }, PageQueryOptions.FetchContent).FirstAsync()!;
         }
 
-        /// <inheritdoc cref="FetchRevisionsAsync(WikiSite,IEnumerable{int},IWikiPageQueryProvider,CancellationToken)"/>
-        public static IAsyncEnumerable<Revision?> FetchRevisionsAsync(WikiSite site, params int[] revisionIds)
+        /// <inheritdoc cref="FetchRevisionsAsync(WikiSite,IEnumerable{long},IWikiPageQueryProvider,CancellationToken)"/>
+        public static IAsyncEnumerable<Revision?> FetchRevisionsAsync(WikiSite site, params long[] revisionIds)
         {
             return FetchRevisionsAsync(site, revisionIds, PageQueryOptions.FetchContent, CancellationToken.None);
         }
 
-        /// <inheritdoc cref="FetchRevisionsAsync(WikiSite,IEnumerable{int},IWikiPageQueryProvider,CancellationToken)"/>
-        public static IAsyncEnumerable<Revision?> FetchRevisionsAsync(WikiSite site, IEnumerable<int> revisionIds)
+        /// <inheritdoc cref="FetchRevisionsAsync(WikiSite,IEnumerable{long},IWikiPageQueryProvider,CancellationToken)"/>
+        public static IAsyncEnumerable<Revision?> FetchRevisionsAsync(WikiSite site, IEnumerable<long> revisionIds)
         {
             return FetchRevisionsAsync(site, revisionIds, PageQueryOptions.FetchContent, CancellationToken.None);
         }
 
-        /// <inheritdoc cref="FetchRevisionsAsync(WikiSite,IEnumerable{int},IWikiPageQueryProvider,CancellationToken)"/>
-        public static IAsyncEnumerable<Revision?> FetchRevisionsAsync(WikiSite site, IEnumerable<int> revisionIds, PageQueryOptions options)
+        /// <inheritdoc cref="FetchRevisionsAsync(WikiSite,IEnumerable{long},IWikiPageQueryProvider,CancellationToken)"/>
+        public static IAsyncEnumerable<Revision?> FetchRevisionsAsync(WikiSite site, IEnumerable<long> revisionIds, PageQueryOptions options)
         {
             return FetchRevisionsAsync(site, revisionIds, options, CancellationToken.None);
         }
 
-        /// <inheritdoc cref="FetchRevisionsAsync(WikiSite,IEnumerable{int},IWikiPageQueryProvider,CancellationToken)"/>
-        public static IAsyncEnumerable<Revision?> FetchRevisionsAsync(WikiSite site, IEnumerable<int> revisionIds, PageQueryOptions options, CancellationToken cancellationToken)
+        /// <inheritdoc cref="FetchRevisionsAsync(WikiSite,IEnumerable{long},IWikiPageQueryProvider,CancellationToken)"/>
+        public static IAsyncEnumerable<Revision?> FetchRevisionsAsync(WikiSite site, IEnumerable<long> revisionIds, PageQueryOptions options, CancellationToken cancellationToken)
         {
             return FetchRevisionsAsync(site, revisionIds, MediaWikiHelper.QueryProviderFromOptions(options), cancellationToken);
         }
@@ -81,7 +81,7 @@ public static ValueTask<Revision> FetchRevisionAsync(WikiSite site, int revision
         /// <para>If there's invalid revision id in <paramref name="revisionIds"/>, an <see cref="ArgumentException"/>
         /// will be thrown while enumerating.</para>
         /// </remarks>
-        public static IAsyncEnumerable<Revision?> FetchRevisionsAsync(WikiSite site, IEnumerable<int> revisionIds, IWikiPageQueryProvider options, CancellationToken cancellationToken)
+        public static IAsyncEnumerable<Revision?> FetchRevisionsAsync(WikiSite site, IEnumerable<long> revisionIds, IWikiPageQueryProvider options, CancellationToken cancellationToken)
         {
             if (site == null) throw new ArgumentNullException(nameof(site));
             if (revisionIds == null) throw new ArgumentNullException(nameof(revisionIds));
@@ -94,10 +94,10 @@ public static ValueTask<Revision> FetchRevisionAsync(WikiSite site, int revision
         public WikiPageStub Page { get; internal set; }
 
         [JsonProperty("revid")]
-        public int Id { get; private set; }
+        public long Id { get; private set; }
 
         [JsonProperty]
-        public int ParentId { get; private set; }
+        public long ParentId { get; private set; }
 
         /// <summary>
         /// Gets the content of the revision.
@@ -145,7 +145,7 @@ public static ValueTask<Revision> FetchRevisionAsync(WikiSite site, int revision
         /// <seealso cref="RevisionFlags.Anonymous"/>
         /// <seealso cref="RevisionHiddenFields.User"/>
         [JsonProperty]
-        public int UserId { get; private set; }
+        public long UserId { get; private set; }
 
         /// <summary>
         /// Gets a <see cref="UserStub"/> containing the name and ID of the user made this revision.
diff --git a/WikiClientLibrary/Pages/WikiPage.cs b/WikiClientLibrary/Pages/WikiPage.cs
index 7d3c6901d..7757fd8e3 100644
--- a/WikiClientLibrary/Pages/WikiPage.cs
+++ b/WikiClientLibrary/Pages/WikiPage.cs
@@ -57,7 +57,7 @@ public WikiPage(WikiSite site, string title, int defaultNamespaceId)
         /// <param name="id">Page ID.</param>
         /// <remarks>The initialized instance does not contain any live information from MediaWiki site.
         /// Use <see cref="RefreshAsync()"/> to fetch for information from server.</remarks>
-        public WikiPage(WikiSite site, int id)
+        public WikiPage(WikiSite site, long id)
         {
             if (site == null) throw new ArgumentNullException(nameof(site));
             Site = site;
@@ -72,7 +72,7 @@ public WikiPage(WikiSite site, int id)
         /// <summary>
         /// Id of the page.
         /// </summary>
-        public int Id => PageStub.Id;
+        public long Id => PageStub.Id;
 
         /// <summary>
         /// Namespace id of the page.
@@ -138,7 +138,7 @@ public IReadOnlyCollection<IWikiPagePropertyGroup> PropertyGroups
         /// See <see cref="EditAsync"/> for more information.
         /// </summary>
         /// <seealso cref="Revision.Id"/>
-        public int LastRevisionId { get; private set; }
+        public long LastRevisionId { get; private set; }
 
         /// <summary>
         /// Content length, in bytes.
diff --git a/WikiClientLibrary/Pages/WikiPageStub.cs b/WikiClientLibrary/Pages/WikiPageStub.cs
index 88c3c782c..e000f73dc 100644
--- a/WikiClientLibrary/Pages/WikiPageStub.cs
+++ b/WikiClientLibrary/Pages/WikiPageStub.cs
@@ -31,14 +31,14 @@ namespace WikiClientLibrary.Pages
 
         /// <summary>The <see cref="Id"/> value used for missing page.</summary>
         /// <remarks>For how the missing pages are handled, see the "remarks" section of <see cref="WikiPageStub"/>.</remarks>
-        public const int MissingPageIdMask = unchecked((int)0x8F000001);
+        public const long MissingPageIdMask = unchecked((long)0x8F00_0000_0000_0001);
 
         /// <summary>The <see cref="Id"/> value used for invalid page.</summary>
         /// <remarks>For how the missing pages are handled, see the "remarks" section of <see cref="WikiPageStub"/>.</remarks>
-        public const int InvalidPageIdMask = unchecked((int)0x8F000002);
+        public const long InvalidPageIdMask = unchecked((long)0x8F00_0000_0000_0002);
 
         /// <summary>The <see cref="Id"/> value used for Special page.</summary>
-        public const int SpecialPageIdMask = unchecked((int)0x8F000011);
+        public const long SpecialPageIdMask = unchecked((long)0x8F00_0000_0000_0011);
 
         /// <summary>The <see cref="Title"/> value used for missing page.</summary>
         /// <remarks>For how the missing pages are handled, see the "remarks" section of <see cref="WikiPageStub"/>.</remarks>
@@ -53,17 +53,17 @@ namespace WikiClientLibrary.Pages
         /// </summary>
         public static readonly WikiPageStub Empty = new WikiPageStub();
 
-        /// <inheritdoc cref="WikiPageStub(int,string,int)"/>
+        /// <inheritdoc cref="WikiPageStub(long,string,int)"/>
         public WikiPageStub(string title, int namespaceId) : this(0, title, namespaceId)
         {
         }
 
-        /// <inheritdoc cref="WikiPageStub(int,string,int)"/>
-        public WikiPageStub(int id) : this(id, null, UnknownNamespaceId)
+        /// <inheritdoc cref="WikiPageStub(long,string,int)"/>
+        public WikiPageStub(long id) : this(id, null, UnknownNamespaceId)
         {
         }
 
-        /// <inheritdoc cref="WikiPageStub(int,string,int)"/>
+        /// <inheritdoc cref="WikiPageStub(long,string,int)"/>
         public WikiPageStub(string title) : this(0, title, UnknownNamespaceId)
         {
         }
@@ -74,9 +74,9 @@ public WikiPageStub(string title) : this(0, title, UnknownNamespaceId)
         /// <param name="id">Page ID. <c>0</c> for unknown.</param>
         /// <param name="title">Page full title. <c>null</c> for unknown. <see cref="string.Empty"/> will be normalized into <c>null</c>.</param>
         /// <param name="namespaceId">Page namespace ID. <see cref="UnknownNamespaceId"/> for unknown.</param>
-        public WikiPageStub(int id, string? title, int namespaceId) : this()
+        public WikiPageStub(long id, string? title, int namespaceId) : this()
         {
-            const int idMasks = SpecialPageIdMask | MissingPageIdMask | InvalidPageIdMask;
+            const long idMasks = SpecialPageIdMask | MissingPageIdMask | InvalidPageIdMask;
             if (id < 0 && (id & idMasks) != id)
                 throw new ArgumentOutOfRangeException(nameof(id),
                     "Invalid page ID. ID should be positive; 0 for unknown; bitwise-or of one or more WikiPageStub.****Mask fields.");
@@ -90,7 +90,7 @@ public static WikiPageStub NewMissingPage(string title, int namespaceId)
             return new WikiPageStub(MissingPageIdMask, title, namespaceId);
         }
 
-        public static WikiPageStub NewMissingPage(int id)
+        public static WikiPageStub NewMissingPage(long id)
         {
             return new WikiPageStub(id, MissingPageTitle, UnknownNamespaceId);
         }
@@ -115,7 +115,7 @@ public static WikiPageStub NewInvalidPage(string title)
         /// <summary>Gets the page ID.</summary>
         /// <value>Page ID; or <c>0</c> if the information is not available;
         /// or <see cref="MissingPageIdMask"/> for the confirmed missing page.</value>
-        public int Id { get; }
+        public long Id { get; }
 
         /// <summary>Gets the full title of the page.</summary>
         /// <value>Normalized or un-normalized page title; or <c>null</c> if the information is not available;
@@ -205,12 +205,12 @@ public static implicit operator WikiPageStub(string? pageTitle)
             return string.IsNullOrEmpty(pageTitle) ? Empty : new WikiPageStub(pageTitle);
         }
 
-        public static implicit operator WikiPageStub(int pageId)
+        public static implicit operator WikiPageStub(long pageId)
         {
             return new WikiPageStub(pageId);
         }
 
-        public static implicit operator WikiPageStub(int? pageId)
+        public static implicit operator WikiPageStub(long? pageId)
         {
             return new WikiPageStub(pageId ?? 0);
         }
diff --git a/WikiClientLibrary/RequestHelper.cs b/WikiClientLibrary/RequestHelper.cs
index fb77302dc..d0dbdec72 100644
--- a/WikiClientLibrary/RequestHelper.cs
+++ b/WikiClientLibrary/RequestHelper.cs
@@ -281,7 +281,7 @@ public static async Task RefreshPagesAsync(IEnumerable<WikiPage> pages, IWikiPag
         /// <remarks>
         /// <para>If there's invalid revision id in <paramref name="revIds"/>, an <see cref="ArgumentException"/> will be thrown while enumerating.</para>
         /// </remarks>
-        public static async IAsyncEnumerable<Revision?> FetchRevisionsAsync(WikiSite site, IEnumerable<int> revIds,
+        public static async IAsyncEnumerable<Revision?> FetchRevisionsAsync(WikiSite site, IEnumerable<long> revIds,
             IWikiPageQueryProvider options, [EnumeratorCancellation] CancellationToken cancellationToken = default)
         {
             if (revIds == null) throw new ArgumentNullException(nameof(revIds));
@@ -291,8 +291,8 @@ public static async Task RefreshPagesAsync(IEnumerable<WikiPage> pages, IWikiPag
             queryParams.Remove("rvlimit");
             var titleLimit = options.GetMaxPaginationSize(site.SiteInfo.Version, site.AccountInfo.HasRight(UserRights.ApiHighLimits));
             // Page ID --> Page Stub
-            var stubDict = new Dictionary<int, WikiPageStub>();
-            var revDict = new Dictionary<int, Revision>();
+            var stubDict = new Dictionary<long, WikiPageStub>();
+            var revDict = new Dictionary<long, Revision>();
             using (site.BeginActionScope(null, (object)revIds))
             {
                 foreach (var partition in revIds.Partition(titleLimit))
@@ -395,7 +395,7 @@ public static async Task<IReadOnlyCollection<PurgeFailureInfo>> PurgePagesAsync(
             return failedPages ?? (IReadOnlyCollection<PurgeFailureInfo>) Array.Empty<PurgeFailureInfo>();
         }
 
-        public static async Task PatrolAsync(WikiSite site, int? recentChangeId, int? revisionId, CancellationToken cancellationToken)
+        public static async Task PatrolAsync(WikiSite site, long? recentChangeId, long? revisionId, CancellationToken cancellationToken)
         {
             if (site == null) throw new ArgumentNullException(nameof(site));
             if (recentChangeId == null && revisionId == null)
diff --git a/WikiClientLibrary/Sites/AccountInfo.cs b/WikiClientLibrary/Sites/AccountInfo.cs
index 678df278e..6d025fc9c 100644
--- a/WikiClientLibrary/Sites/AccountInfo.cs
+++ b/WikiClientLibrary/Sites/AccountInfo.cs
@@ -20,7 +20,7 @@ internal AccountInfo()
         }
 
         [JsonProperty]
-        public int Id { get; private set; }
+        public long Id { get; private set; }
 
         [JsonProperty]
         public string Name { get; private set; }
diff --git a/WikiClientLibrary/UserStub.cs b/WikiClientLibrary/UserStub.cs
index d50f414bf..51eb3531b 100644
--- a/WikiClientLibrary/UserStub.cs
+++ b/WikiClientLibrary/UserStub.cs
@@ -13,15 +13,15 @@ namespace WikiClientLibrary
 
         public static readonly UserStub Empty = new UserStub();
 
-        public UserStub(string name, int id) : this(name, id, Gender.Unknown, null)
+        public UserStub(string name, long id) : this(name, id, Gender.Unknown, null)
         {
         }
 
-        public UserStub(string name, int id, Gender gender) : this(name, id, gender, null)
+        public UserStub(string name, long id, Gender gender) : this(name, id, gender, null)
         {
         }
 
-        public UserStub(string name, int id, Gender gender, string? siteName)
+        public UserStub(string name, long id, Gender gender, string? siteName)
         {
             Name = name ?? throw new ArgumentNullException(nameof(name));
             Id = id;
@@ -34,7 +34,7 @@ public UserStub(string name, int id, Gender gender, string? siteName)
 
         /// <summary>Gets user ID on the MediaWiki site.</summary>
         /// <value>User ID on the MediaWiki site, or <c>0</c> for anonymous users.</value>
-        public int Id { get; }
+        public long Id { get; }
 
         /// <summary>Gets user's gender.</summary>
         public Gender Gender { get; }