Branch mainnet has been updated to be in sync with mainnet-staging (commit hash 7a87782010fe68ac05dec2e986b708abfa9184d2).
This major release changes the storage backend and requires specific care when updating.
Changelog and upgrade instructions can be found in the release documentation page: https://tezos.gitlab.io/releases/december-2019.html
Note that if you are not using mainnet-staging already, upgrading will take time. It takes about an hour if you are using the full mode and several days if you are using the archive mode.
The release documentation contains several upgrade paths depending on your situation to minimize the downtime of your node. Take your time to choose carefully.
If you have to temporarily use the old LMDB backend, you can use the branch named mainnet-lmdb. Note that not only does it not contain the new storage backend, it also does not contain the new features of this release.
