Xawtv3 remained without updates for a long time. So, distros were adding bug fix patches on their packages. Also, some tools used to support just V4L1 API.
A series of patches were added, incorporating the bugfixes found on the distros and converting it to use V4L2 API.
After a long time without updates, keeping on version 3.95 since April 2010, Several bugs were discovered and fixed on distros. However, as the package were not maintained anymore, those fixes never reached upstream.
I and Dmitry Butskoy (Fedora maintainer for xawtv) did an effort to port the patches we found on some distros and port them into Xawtv3. So, version 3.100 should have less bugs than version 3.95.
Another series of patches were added, converting it to use V4L2 API only, as V4L1 API was deprecated and removed from upstream on kernel 2.6.38.