Happy Birthday Max
I know with cat food for seniors there is a change in he %age of protein in the food.
My last dog had a problem with bladder stones in his final months and the vet said that males were prone to this.
I am sure that some doggy expert will be along to give you a better answer.
One of my stupid fekkin' cats has just stomped all over my printer, turning it on and is now wandering over the desk and keyboard in an attempt to get to the other half of the chew that he has just demolished - which is is destined for his sister. Dogs just don't do stuff like this - do you want to swap?