11-28 to 11-32 advise please.

You can run a 32 on all short cage rear derailleurs both 10 speed and 11 speed. It works perfectly, so you only need to change chain length if you want to run big big (cross chained). Wind the B screw in a bit and it will shift great. Look on youtube for tutuorials.

My Endurace is running a 32 as standard.

Having looked at canyon, it says the current model has a GS rear derailleur. If that's the case with your bike, just stick on a 11-32 cass. Slight adjustment of the B screw, job done

If you have done a lot of miles you should probably replace the chain too

Since you already have a 28t Cass, you might get away with just the Cass. Adjustment of the 'B' screw to bring the derailleur back to clear the 32t sprocket. If it doesn't clear then a 'gs' rear derailleur will be required.
Shimano are overly cautious on the specification as to what will fit and what won't. If you're definitely going to get a 11-32, get this first and try if it works, then get the derailleur if doesn't work.

You'll need a Medium (GS) Rear Derailleur. Other than that you should be good to go. 

Best thing I did getting 11–32 - saved my knees.