Last change to sofia-sip at sourceforge.net was in 2011.
It seems linphone.org has steadily maintained their fork, arguably
effectively taking over as new upstream.
Seems their source is maintained at git://git.linphone.org/sofia-sip.git
with Github mirror https://github.com/BelledonneCommunications/sofia-sip
- both places using branch "bc" (with branch "master" preserving the
previous home sourceforge.net).
Another fork at https://github.com/AzettiNetworks/sofia-sip has a range
of patches mainly fixing memory leaks - possibly interesting to cherry-
pick but does not seem steadily maintained like the Linphone.org fork.
I suggest to treat the linphone.org fork as new upstream of sofia-sip
and consider applying the Azetti changes as well.
- Jonas