While the jump from FORTRAN II to FORTRAN IV involved changes to FORTRAN that meant that FORTRAN IV was not upwards compatible with FORTRAN II (although most of the changes involved little-used features, with only one being major: the fact that function names no longer ended in F), since then upwards compatibility has been preserved much more carefully.
In Fortran 90, some old features of FORTRAN were identified as being deprecated; these were removed in FORTRAN 95. Among them were the H format code, and the assigned GO TO statement. The H format code would only be useful for automatically generating programs, and, while I miss the assigned GO TO, I can understand that it is regarded as unstructured and unnecessary. Three other features were dropped that were obscure enough that even I don't miss them. As for sense lights and sense switches, they appear to have vanished at the time of FORTRAN 77, if not FORTRAN 66.
The features of High Performance Fortran were found to be so useful that they were incorporated into the Fortran language with this version of the standard.
Also added were provisions to handle the new facilities offered by IEEE 754 floating-point numbers.
The jump to Fortran 95 from Fortran 90, however, was nowhere nearly as major as that from Fortran 77 to Fortran 90.