[opencms-dev] Upgrading from 7.5.4 to 9: best practices

[Roman Uhlig]

After a long absence from OpenCms because of freelancing in the field of
mobile apps, I'm now facing the task of upgrading several OpenCms 7.5.4
installations running on Debian and GenToo Linux machines.

My question is: should I directly upgrade to the latest version or
should I go in several steps to not get overwhelmed by the changes that
may occur due to the upgrade?

I'm asking because I already tried an update to OpenCms 8 according to
the document from Michael Emmerich (OpenCms Days 2011). There he says:
"Your existing OpenCms 7.x webapp will run in OpenCms 8 – most likely
without any changes". That did not work for me, many of our OpenCms
webapps did not work anymore as expected after the update.

Any hint how to progress in this matter whould be very appreciated.

Thank you very much,
Roman