There have been changes to the Starcom21 towers in the vicinity of Peoria since LE agencies switched to Starcom 21 system. The SC21 sites in the Peoria area are now simulcast LSM sites and would assume there would be ISP D-8 traffic on the simulcast sites. Looking at the Database I don’t see any other changes for ISP District 8.
Whether you hear ISP District 8 would be dependent on which sites you monitor and radios which affiliate with those sites. Normally any site in the geographic area of the District 8 counties will carry ISP District 8 A Talk Group plus the District 8 ISPERN TG. Any other TG’s heard will probably only be carried on affiliated sites. An example would be two ISP units on car to car voting two different sites. Your scanner would have to be receiving either of the two sites to hear the car to car traffic.
If there has been a change to the control channel frequency on the site you receive you’d have to have any new control channel frequency programmed into your scanner.
Did you inadvertently lock out/avoid ISP District 8 Talk Group? If there are very few units on Patrol I have seen where certain Districts are told to switch to a different Talk Group if there is a shortage of tele-communicators. Since the consolidation of dispatch ISP District 8 was being Dispatched by Springfield if I remember correctly. On the mid night shift it was common for multiple Talk Groups to be patched together or Troopers were told to switch Talk Groups since there were fewer TC’s working.
Here is a link to the Peoria Simulcast page from the RR database and the frequencies for the site at the District 8 State Police Post.
https://www.radioreference.com/apps/db/?siteId=9384
Metamora Woodford County
769.15625 | 770.20625 | 772.41875a | 773.08125 | 774.29375c | 774.59375 | 853.425 |