If necessary, a server can be reverted to the previous version using the revert-update tool. The tool accesses a log of file actions taken by the update tool to put the file system back to its prior state. If multiple updates have been run, the revert-update tool can be used multiple times to revert to each prior update sequentially. For example, the revert-update command can be run to revert to the server's previous state, then run again to return to its original state. The server is stopped during the revert-update process.
Note:

Reverting an update is not supported for upgrades to version 7.0, due to the topology backend changes.

Use the revert-update tool in the server root directory revert back to the most recent version of the server:
$ PingData-server-old/revert-update