If you raise it from 65 to 68 in one shot, then it’ll cause lots of resentment. Witness what happened in France a year or two ago!
If you raise it from 65 to 65.15 one year, it’ll cause a lot less resentment. And then you raise it from 65.15 to 65.3 the next year. And so on. Basically, you spread the resentment widely in time. That’s pretty much what the Germans are thinking of doing.