This assumes you want to downgrade your OctoPrint installation setup (which you set up following the general installation instructions or one of the setup guides on the wiki) to
<old_version>. Your checkout folder is at
cd /path/to/OctoPrint source venv/bin/activate git fetch git checkout master git reset --hard <old_version> python setup.py clean pip install .
Then restart OctoPrint.
If you did not follow the general installation instructions or any of the manual setup guides on the wiki, you might have to adjust the path to the virtual environment into which you installed OctoPrint (
venvin the above steps).