diff --git a/BuildVersionSpecifier.swift b/BuildVersionSpecifier.swift
new file mode 100755
index 00000000..21920c1d
--- /dev/null
+++ b/BuildVersionSpecifier.swift
@@ -0,0 +1,85 @@
+#!/usr/bin/env swift
+
+// Copyright (c) 2021 and onwards The vChewing Project (MIT-NTL License).
+/*
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+1. The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+2. No trademark license is granted to use the trade names, trademarks, service
+marks, or product names of Contributor, except as required to fulfill notice
+requirements above.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+import Cocoa
+
+extension String {
+	fileprivate mutating func regReplace(pattern: String, replaceWith: String = "") {
+		// Ref: https://stackoverflow.com/a/40993403/4162914 && https://stackoverflow.com/a/71291137/4162914
+		do {
+			let regex = try NSRegularExpression(
+				pattern: pattern, options: [.caseInsensitive, .anchorsMatchLines])
+			let range = NSRange(self.startIndex..., in: self)
+			self = regex.stringByReplacingMatches(
+				in: self, options: [], range: range, withTemplate: replaceWith)
+		} catch { return }
+	}
+}
+
+var verMarket: String = "1.0.0"
+var verBuild: String = "1000"
+var strXcodeProjContent: String = ""
+var dirXcodeProjectFile = "./vChewing.xcodeproj/project.pbxproj"
+var dirPackageProjectFile = "./vChewing.pkgproj"
+var dirUpdateInfoPlist = "./Update-Info.plist"
+var theDictionary: NSDictionary?
+
+if CommandLine.arguments.count == 3 {
+	verMarket = CommandLine.arguments[1]
+	verBuild = CommandLine.arguments[2]
+
+	// Xcode project file version update.
+	do {
+		strXcodeProjContent += try String(contentsOfFile: dirXcodeProjectFile, encoding: .utf8)
+	} catch {
+		NSLog(" - Exception happened when reading raw phrases data.")
+	}
+
+	strXcodeProjContent.regReplace(
+		pattern: #"CURRENT_PROJECT_VERSION = .*$"#, replaceWith: "CURRENT_PROJECT_VERSION = " + verBuild + ";")
+	strXcodeProjContent.regReplace(
+		pattern: #"MARKETING_VERSION = .*$"#, replaceWith: "MARKETING_VERSION = " + verMarket + ";")
+	do {
+		try strXcodeProjContent.write(to: URL(fileURLWithPath: dirXcodeProjectFile), atomically: false, encoding: .utf8)
+	} catch {
+		NSLog(" -: Error on writing strings to file: \(error)")
+	}
+	NSLog(" - Xcode 專案版本資訊更新完成：\(verMarket) \(verBuild)。")
+
+	// Packages project file version update.
+	theDictionary = NSDictionary(contentsOfFile: dirPackageProjectFile)
+	theDictionary?.setValue(verMarket, forKeyPath: "PACKAGES.PACKAGE_SETTINGS.VERSION")
+	theDictionary?.write(toFile: dirPackageProjectFile, atomically: true)
+	NSLog(" - Packages 專案版本資訊更新完成：\(verMarket) \(verBuild)。")
+
+	// Update notification project file version update.
+	theDictionary = NSDictionary(contentsOfFile: dirUpdateInfoPlist)
+	theDictionary?.setValue(verBuild, forKeyPath: "CFBundleVersion")
+	theDictionary?.setValue(verMarket, forKeyPath: "CFBundleShortVersionString")
+	theDictionary?.write(toFile: dirUpdateInfoPlist, atomically: true)
+	NSLog(" - 更新用通知 plist 版本資訊更新完成：\(verMarket) \(verBuild)。")
+
+}