Case study · Cloud Migration

Migrating Mautic 5.2.9 to 7.1.2 across two majors, with 45,522 contacts live

Our own marketing automation platform had sat two major versions behind for the better part of a year. We moved it, in production, and published what went wrong on the way.

Work carried out on our own production systems. Published 2026-07-09.

Versions crossed

5.2.9 → 7.1.2

Contacts migrated

45,522

Doctrine migrations run

90, cleanly

Data corruption

None

The situation

• Mautic 5.2.9 running in Docker on a Linode 4GB instance with MariaDB 10.6 in a sidecar container.
• 45,522 contacts, 51 forms, 24 campaigns and 91 email templates in live use — the platform could not simply be switched off.
• Two major versions behind, which Mautic’s in-app updater does not reliably cross.

What we did

• Stood up a fresh 7.1.2 stack on new volumes rather than upgrading in place, so the running instance stayed untouched.
• Bulk-imported contacts from a CSV export while the old instance kept serving.
• When the fresh install was accidentally overwritten, ran the direct Doctrine migration path — the one everyone advises against — rather than restarting from scratch.

Outcome

• Ninety Doctrine migrations executed cleanly across two major versions with no data corruption.
• One silent NULL landmine surfaced during the run and was fixed with a single line of SQL.
• The direct Doctrine path succeeded precisely where the in-app updater fails, which is now our documented route for two-major upgrades.

Read the full technical write-up →