Private key size

As I have noticed in Advanced Private Key Options Topic (see, the key size of 4096 is not recommended as this will cause a compatibility issue. I would like to know which particular compatibility issues could happen.

So far I have used a code signing certificate from another CA with key size of 4096 for signing EXE files a MS Ofiice VBA projects without any problems. I want to buy a Comodo code signing certificate so I am not sure whether use the same key size of 4096 or go to the lower security with size of 2048.

Thank you

Is this a resolved topic and there are no compatibility issues anymore?
Can someone give a answer please, I have the same question as George as I founded the old topic.