There's a new development diary here's a sample of how summoning affects combat. Summoning familiars are there to support you, whichever combat class your character is using, so we decided it made sense for them to add to your Combat level in a similar way to how Prayer does. Adding Summoning to the Combat level calculation means that the maximum will increase from 126 up to 138. It's a new goal for anyone who already has a level 126 character, or just for anyone who enjoys training skills.