Hi,
In-place upgrade is the correct approach.
Recent builds have had a security focus, so are more likely to have breaking changes fixable with configuration. Test the upgrade against a non-production environment and take notes while fixing issues prior to upgrading production.
Fully-hosted with Adobe I would recommend exporting out any conflict-prone objects such as altered forms, though you're on-premise so relatively safe here. As always, take a full snapshot of the db prior to performing any upgrade.
Adobe has a good guide for Windows deployments: https://helpx.adobe.com/campaign/kb/acc-build-upgrade.html
Thanks,
-Jon