# 1 Backward Compatible Software

List of Open Source software projects that officially pledge to never (again) release a new version with notable breaking API changes and guarantee to eternally stay backward compatible (sometimes also called "upwards" compatible):

Project Home page Description Backward compatibility status Pledge Deprecation strategy Since
Go https://go.dev Programming language by Google Best effort Go 2 [...] is never going to happen., [1] https://go.dev/wiki/Deprecated
Linux kernel https://kernel.org OS kernel Compatible WE DO NOT BREAK USERSPACE!
JavaScript Various engines Language specification Compatible Browsers are unwilling to break web pages for their users, no matter how much you think the developers of those websites deserve it.

# 2 Somewhat stable Software

The following Open Source software projects are known for being very conservative with breaking changes but have made no promise so far.

# 3 Upcoming Incompatible Software

The following is a list of notable software projects that may appear to have been backward compatible in recent times, but have explicitly stated at least the possibility of another breaking version:

# 4 Backwards Incompatible Software

The following is a list of notable software projects that have a recognition of being backward compatible but have shown to not strictly follow that rule: