kampfgnu

//First, in your working tree, locally rename master to something else.
git branch -m master old-dev

//Renaming a branch does work while you are on the branch, so there's no need to checkout something else.
//Then, locally rename the maintenance branch (2.63-branch) to master:
git branch -m 2.63-branch master

//Now, time to mess with the remote. Just in case you screw up, you might want to make sure you have a current backup. First, //delete the remote's master:
git push origin :master

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git push origin <branchname>
git branch --set-upstream <branchname> origin/<branchname>

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//server side:
GIT_DIR=project.git git init
cd project.git
git --bare update-server-info
cp hooks/post-update.sample hooks/post-update

//on client side:
git clone ssh://<username>@<remote-git-hostname>/path/to/dir.git

//on first push to master: