diff --git a/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift b/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
index d4c4c737..1cd57c99 100644
--- a/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
@@ -53,6 +53,7 @@ public protocol PrefMgrProtocol {
   var forceCassetteChineseConversion: Int { get set }
   var showReverseLookupInCandidateUI: Bool { get set }
   var autoCompositeWithLongestPossibleCassetteKey: Bool { get set }
+  var shareAlphanumericalModeStatusAcrossClients: Bool { get set }
   var cns11643Enabled: Bool { get set }
   var cassetteEnabled: Bool { get set }
   var symbolInputEnabled: Bool { get set }
diff --git a/Packages/vChewing_Shared/Sources/Shared/Shared.swift b/Packages/vChewing_Shared/Sources/Shared/Shared.swift
index 910f841d..650087a0 100644
--- a/Packages/vChewing_Shared/Sources/Shared/Shared.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/Shared.swift
@@ -66,6 +66,7 @@ public enum UserDef: String, CaseIterable {
   case kForceCassetteChineseConversion = "ForceCassetteChineseConversion"
   case kShowReverseLookupInCandidateUI = "ShowReverseLookupInCandidateUI"
   case kAutoCompositeWithLongestPossibleCassetteKey = "AutoCompositeWithLongestPossibleCassetteKey"
+  case kShareAlphanumericalModeStatusAcrossClients = "ShareAlphanumericalModeStatusAcrossClients"
 
   case kUseIMKCandidateWindow = "UseIMKCandidateWindow"
   case kHandleDefaultCandidateFontsByLangIdentifier = "HandleDefaultCandidateFontsByLangIdentifier"
diff --git a/Source/Modules/PrefMgr_Core.swift b/Source/Modules/PrefMgr_Core.swift
index 22a1829a..81c8a1a1 100644
--- a/Source/Modules/PrefMgr_Core.swift
+++ b/Source/Modules/PrefMgr_Core.swift
@@ -152,6 +152,9 @@ public class PrefMgr: PrefMgrProtocol {
   @AppProperty(key: UserDef.kAutoCompositeWithLongestPossibleCassetteKey.rawValue, defaultValue: true)
   public var autoCompositeWithLongestPossibleCassetteKey: Bool
 
+  @AppProperty(key: UserDef.kShareAlphanumericalModeStatusAcrossClients.rawValue, defaultValue: false)
+  public var shareAlphanumericalModeStatusAcrossClients: Bool
+
   // MARK: - Settings (Tier 2)
 
   @AppProperty(key: UserDef.kUseIMKCandidateWindow.rawValue, defaultValue: false)
diff --git a/Source/Modules/PrefMgr_Extension.swift b/Source/Modules/PrefMgr_Extension.swift
index e3108b84..f84fef96 100644
--- a/Source/Modules/PrefMgr_Extension.swift
+++ b/Source/Modules/PrefMgr_Extension.swift
@@ -20,6 +20,7 @@ extension PrefMgr {
       disableShiftTogglingAlphanumericalMode = true
       togglingAlphanumericalModeWithLShift = false
       showReverseLookupInCandidateUI = false
+      shareAlphanumericalModeStatusAcrossClients = false
     }
     // 自動糾正選字鍵 (利用其 didSet 特性)
     candidateKeys = candidateKeys