I heard somewhere that there are considerations that need to be taken into account with regards to rotating your keys and what your cold counter shows after upgrading to 1.35.x. Is this correct and can someone advise on what we need to be aware of?

from what I heard the op.cert will be invalid if u set the next increment number > x + 1 (where x is the current number) when u rotating the KES

Cheers,

so how do we rotate keys using cntools that is different to normal?

Its the same, the only difference is that now u can rotate x time the KES with no problemsâ€¦ after Vasil HF this will be an issue u must use the increment number exactly + 1 from last one used

If for example now u are using 7 and u will set next increment number to 10 it will work (as long the new number is > than 7), but after Vasil HF it is mandatory to use 8 (7 last one used + 1)

more info how to find the current number used

So adapools shows my OpCert as 9 and my cold.counter is showing next certificate number is 10 so does that mean I can just rotate the keys as normal?

Yes, this is the right way

Great thanks for clarifying that

Here is a good tutorial about it Adjust Node.Counter for KES - How to Guides for Coincashew Method Cardano SPOs

You need to increase the counter by +1, but it needs to be +1 from the last counter on the blockchain. So if you havenâ€™t minted a block for a while you need to have your KES at +1 from the last time you minted a block.