. Only internal bug fixes. When new features are added the second number is incremented. Last time it occured (5.1 -> 5.2) it was to support the new option to disable the active cruise control.BTW, if you do not have any problem with 5.2.A.R9 then 5.2.C.R1 will not bring anything new but maybe some new nasty bugs. Only internal bug fixes. When new features are added the second number is incremented. Last time it occured (5.1 -> 5.2) it was to support the new option to disable the active cruise control.
BTW internal bug fixes are not a bag thing right. Maybe they improved the speed and stability too.