I think we've fixed the major issues identified by Stig, Jim, and others so I'd like to release 2.5.0 on February 6. This would let us release 2.6.0 this spring, followed by 3.0.0 in the fall:
March: Create master-2.6 after one or two 2.5.x releases.
April: Release 2.6.0, probably after SharkFest Asia.
August: Release 2.9.0.
September 7, 2018: The 2.2 branch reaches EOL.
September or October: Create master-3.0 after one or more 2.9.x releases.
October or November: Release 3.0.0, either before or after SharkFest Europe.
As discussed on this list and (IIRC) at SharkFest EU we can start removing legacy support in master after master-2.6 is branched. This includes, but is not limited to:
- The GTK+ UI
- Older versions of GLib
- Qt 4.8
