concrete5 version 8.3.0 requires that you update to 8.2.1 before you can upgrade to 8.3.0. This is because the migrations need to run in a very precise order for 8.3.0, since it changes how some important underlying database tables are structured. This can cause a problem for sites that are on migrations passed 8.2.1, but aren't completely updated to 8.3.0.
If you are trying to update to 8.3.0 via composer or from a release candidate, and receive complaints about a missing
cIsDraft column in the Pages table, run this command from your web root, when logged in over ssh or in terminal:
concrete/bin/concrete5 -n migrations:execute 20170803000000
This will create the cIsDraft column, and make sure that any existing page drafts are migrated to using this new column. This should allow the rest of the updates to work fine. After this, you can run
to ensure that your database is fully up to date.