API version and shared dll name

Hi,
I was working on the 1.8.7 package for cygwin and I noticed that
the shared dll's are now named cyghdf5-7.dll , cyghdf5_hl-7.dll
while on 1.8.6 the outcome was cyghdf5-6.dll , cyghdf5_hl-6.dll.

As 1.8.6 was the first 1.8 series that I packaged, the -6 extension
was not a problem, as the API was surely different from 1.6 series.

Question:
- there is a API change between 1.8.6 and 1.8.7 that requires
  a version name bump ?
  As simple test, I renamed cyghdf5-7.dll in cyghdf5-6.dll and used with
  some program linked to hdf5 and I had no problem.

Regards
Marco

PS: I hope that this time the mail pass through. The two previous
tentatives seem
disappeared in /dev/null