Yes. Minor updates and hotfixes (like the 11.5.1.2 patch) are free for all users who hold a valid licence for that version.
Lumion offers a free, fully functional 14-day trial. This is ideal for testing the software on a specific project or seeing how it performs on your hardware. patch lumion 11
: Resolved an issue where models assigned to a layer became invisible after hiding and unhiding that layer. OpenStreetMap (OSM) Correction patch lumion 11
If you are looking for the official improvements and "patches" released during the Lumion 11 lifecycle, the software introduced several transformative features for architectural visualization: Orthographic View patch lumion 11