indicates versions without null safety support

Question

I'm tryna enabled null-safe property. that's why I wrote "dart pub outdated --mode=null-safety" but I got error below:

indicates versions without null safety support

Answer 1

I don't think that's an error, the message is letting you know that the x indicates dependencies with no null safety, while the ✓ indicates versions with null safety.

It would then normally go on to list all of your dependencies with either a x or a ✓, but it doesn't because all your dependencies are null safe, so there is no need to (see the next line on your "error").