I believe this is the changelog for 1.20
Content
Cars:
-Added Stock Car V8 2014 season to Stock Car V8 series
-Added Formula Extreme series
-Added Formula Vee series
-Completed full Formula V12 field + updated graphics
Tracks
-Buenos Aires (4 layouts)
-Spielberg (2 layouts)
-Spielberg Historic
Features & fixes:
-Added DRS functionality + rules (for F-Extreme / f-Reiza)
-Added multiple qualifying rules (f1 style / Stockv8)
-Added option to restrict prime / option tire compound selections per track
-Revised tire physics on all cars in preparation to new tire model features currently in development
-Added multiple tire compound options with corresponding tirewall colors to F-Extreme / F-Reiza
-Adjusted dirty air physics for more realistic behavior
-Adjusted engine cooling properties in all cars
-Adjusted AI performance for wider range specially in lower strentgh settings, and more consistency all around from track to track, series to series
-Fixed bug with AI performance discrepancy from quali to race (RaceQualRatio=XX parameter now works in AIW files, lower than 1.0 value will result in slower qual times relative to race, higher values will do the opposite. By default AI should be about 2% faster in quali)
-Increased rearview mirror resolution for all cars
-Corrected FOV / POV + tv cameras to the same standards for all cars
-Updated rumble sounds to be more "bassy" on all cars (for Buttkicker and other similar systems)
-Adjusted trackside cameras in all tracks for more realistic framing / tracking
-Adjusted some inconsistent road & terrain properties, fixing some overdone high frequency bumps
-Various environmental / lightining enhancements (new skies / fog and other updated shaders)
-Introduced new Foliage shader which looks better & is more optimized to provide performance boost
-Added 3d tyre lods at Granja Viana to help ease performance issues
-Added 3d Armco at Interlagos