JULES migration to cylc 8 - ServiceFileError

Hello,

I’ve been trying to migrate my old cylc 7-compatibe rose suite for running JULES to cylc 8, but when I validate the suite I get the following output:

[jmac87@cylc2 roses]$ cylc validate u-dp235

WARNING - Backward compatibility mode ON

ServiceFileError: Workflow database is incompatible with Cylc 8.4.1, or is corrupted.

If I ignore this error and try and “play” the suite anyway, I get the same error:

[jmac87@cylc2 roses]$ cylc play u-dp235
ServiceFileError: Workflow database is incompatible with Cylc 8.4.1, or is corrupted.

I’ve tried searching online for a solution but I can’t find one. Any ideas what this error means and how I can fix it?

Many thanks

Jon