This version is not binary compatible with previous IW 15.0.18, meaning that 3rd party dependent libraries (e.g. TMS or CG Dev Tools) need to be recompiled from sources.
somehow "around" tonyzhou question : in the download page it says : "setup-IW15.0.17.exe is compatible with IW15.0.17 only" but there is setup-IW15.0.18.exe.
so... is this file for 15.0.18 only? 15.0.17 only? or can we install setup-IW15.0.18.exe in an iw 15.0.17 installation ? sorry, it's not so clear for me.
but yes, i would love to see a new version for 15.0.19...