The final cut of TMC Podcast #27 is available now with topics time-stamped. We discussed: Consolidation in LiDAR manufacturers; Volvo EX90 shipping with LiDAR; FSD Beta Full Release in N.A.; FSD detecting autopilot cheats, Gwen Shotwell directly overseeing SpaceX Starship; and more. You can watch it now on YouTube. We should have it published to podcast networks shortly.
Seems people have had trouble installing 4.9 (mine failed and they had to push another install update to me), so my guess is that 4.18 is just an updated version of 4.9 to ensure that install issues are fixed.
2018.10.4 seems to be for the old, um, original MCU, so probably no 3 will get it. Have to wait for a version for the new MCU (S/X) or the 3. Probably the same base code, and then a version for the UI for the 3.