How to fix it?

[rkverma2022]

mylibmanager version 2_1_0] flutter pub add wifi_connect The current Dart SDK version is 3.3.3.

Because mylibmanager depends on wifi_connect any which doesn't support null safety, version solving failed.

The lower bound of "sdk: '>=2.1.0 <3.0.0'" must be 2.12.0 or higher to enable null safety. For details, see https://dart.dev/null-safety exit code 65