Currently, only Live Enhancement supports 4K image quality. Single frames are still saved in 1080p, and deep sky post-stacking does not yet support 4K. Therefore, previous FIT files cannot achieve 4K quality.
The 4K mode must be enabled before enhancement begins; it cannot be turned on during capture. Once you exit Stargazing mode, 4K will be automatically disabled and needs to be re-enabled upon re-entry.