I recently updated the Unison version in my [PPA](https://launchpad.net/~pascal-bach/+archive/unison](https://launchpad.net/~pascal-bach/+archive/unison).
The current version is 2.40.102. This version is taken from the Debian git sources and build without modifications.
The package is available for the following Ubuntu versions:
- 10.04 LTS (lucid)
- 12.04 LTS (precise)
- 12.10 (quantal)
- 13.04 (raring)
If you encounter any problems please let me know.