Upgrade to 2.9.x

I am currently running Devonthink Pro Office 2.7.7 and just noticed that it is no longer upgrading, i.e. even when clicking “Check for Updates” (and the preferences window records the current/time date that last checked), no updates are found and nothing happens. What do I need to do to upgrade to latest 2.9.x? Thanks.

Just download the disk image from our website and replace the old version with the downloaded one on the disk image:
devontechnologies.com/download