What will be the upgrade path to Python 3.x for Google App Engine Applications?

What is required to make the transition to Python 3.x for Google App Engine?

I know Google App Engine requires the use of at least Python 2.5. Is it possible to use Python 3.0 already on Google App Engine?

Which version of Python is used in Google?

Google Colab uses Python 3.6. 9 as of 2021. The only way to use Python 3.8 would be to connect to a local runtime.

It is impossible to currently use Python 3.x applications on Google App Engine. It's simply not supported, and I'd expect to see support for Java (or Perl, or PHP) before Python 3.x.

That said, the upgrade path is likely to be very simple from Python 2.5 to Python 3.x on App Engine. If/when the capability is added, as long as you've coded your application anticipating the changes in Python itself, it should be very straightforward. The heavy lifting has to be done by the Google Engineers. And you'll no doubt be able to keep your application at Python 2.5 for a long while after Python 3.0 is available.