that's why i'm recommending to try to make the changes more open ended, like instead of adding one field to something, instead add a flexible type of field like tags, so that parsing doesn't break so easily on unrecognised field names (tag index zero in each tag) 

 then you don't even really need to specify it in a NIP PR until you have the necessary implementation ready, meanwhile other clients don't choke on the new tag types... nonbreaking changes > breaking changes