Looking at the Gainsville TX FD's FCC license (WQIN432 -
ULS License - Public Safety Pool, Conventional License - WQIN432 - GAINESVILLE, CITY OF), it appears that they've simply added the digital emission designator for standard P-25 digital to their existing license so the frequency won't change, but they'll move from standard analog to P-25 digital. They're license allows both modes so they may possibly switch between the two as a backup, if necessary.
If you click on the frequency it'll show 11K0F3E - standard narrow-band analog voice and 8K10F1E - Standard P-25 digital voice. If you see the old emission mode of 20K0F3E, that's for standard wide-band analog voice.
Please note that the PL tones or digital equivalent NAC is not regulated by the FCC, but is assigned by the agency so you'll need to do a scan to see what they're using, if anything. Once you confirm that they're using P-25 digital on those frequencies (and found any associated NAC), please submit an update to the RR Database so the changes can be published.