In reaction to the recent release of Moodle 2.1, the branch 2.2dev was created in AMOS repository database today. From now on, it is language pack maintainers' responsibility to merge translations from 2.1 (or 2.0) into the 2.2dev manually. Note that there is a merge tool available to this task easier.
At the same time, we removed 1.6, 1.7 and 1.8 branches from the AMOS repository. These versions are not supported any more and their data just occupied 1.5 millions of records (out of 5.4 millions total) in the AMOS repository database. Note that every branch in AMOS contains the full history of the previous branch anyway so there should be no significant data loss. In fact, because Moodle 1.x did not use branches for lang packs, all 1.6, 1.7, 1.8 and 1.9 actually contained the same data.