How can I replace the latest firmware with the older firmware for Form 3?
You can check in preform if there are updates and update it from there.
Sounds like he want to install an older version, not a newer one. Does Formlabs or someone else have a repository for firmware versions?
@MattiaMercante keeps couple of archive threads, one for older Preform versions, and one for older Firmware, but the Firmware one, only covers Form 2.
You might want to contact him to see if he has started archiving any of the Form 3 firmware.
Dear orwo and Dudemeister I am going to upload on thread “Firmware older version” the Form3 files. In meantime, orwo, you can take a look here: https://support.formlabs.com/s/article/Firmware-Release-Notes?language=it