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If you can, please switch your non-playground code dependencies to this release version. If you cannot, remember to switch it them to 0.10.0-SNAPSHOT.
Any development which is done on v0.9.x should, of course, also be merged into master. The cleanest way to do this is to develop on a personal branch, which is branched off master before today, and, when you're finished, merge that branch into both v0.9.x and master.