In general all APIs not under an experimental namespace can only change when changing the major version of TF (like TF 1.x → TF 2.x). We are guaranteeing that code written for TF 2.1 would still work in TF 2.42 if it only uses APIs outside of experimental (there are some exceptions where APIs that are not frequently used but are very broken might break in between minor versions but we will notify this change well in advance)