Following the logic in this file / commit, it looks like the version numbers for the libhdf5 and libhdf5_fortran shared libs were accidentally incremented with the latest release. (Forcing rebuilds in packaging systems for dependencies.)
Following the logic in the file, it looks like LT_VERS_AGE (and LT_F_VERS_ARG) should have been incremented along with LT_VERS_INTERFACE (and LT_F_VERS_INTERFACE). (Should either increment along with (compatible + new ABI), or go to zero (incompatible ABI), not remain static when its “parent” version increments.)
The release has been cut at this point, so mainly bringing it to your attention for future updates.