version

1.0.0+1

The version number is three numbers separated by dots,
such as 1.0.0 in the example above, followed by an optional
build number such as 1 in the example above, separated by a +.

Both the version and the build number can be overridden in
flutter build ipa by specifying --build-name and --build-number,
respectively.

In iOS, build-name uses CFBundleShortVersionString
while build-number uses CFBundleVersion.
Read more about iOS versioning at Core Foundation Keys
on the Apple Developer’s site.

You may also override the pubspec.yaml build name and number in Xcode:

Open Runner.xcworkspace in your app’s ios folder.

Select Runner in the Xcode project navigator, then select the
Runner target in the settings view sidebar.

In the Identity section, update the Version to the user-facing
version number you wish to publish.