A three year old package would be an issue with Flutter. The move to Dart 2 was not backwards compatible.
That said, there's an effort in the community to find maintainers for older packages that people find useful. If you come across something that you need, post back, or shoot me an email.
The biggest gripe I have with React-Native is the many JS packages on npm that we can't use due to how the code is exported. It's a huge hack job, which Flutter absolutely destroyed by having everything I needed as a package that just worked.
One thing I'm looking at on Flutter, is how their public packages age. If I can't use a 3 year old package on modern day Flutter, there will be some big problems coming soon.