PS²: According to this forum thread: Provision Cisco CP8841 to FreePBX using Chan-SCCP - #15 by tmittelstaedt
These phones do not have SCCP firmware, but SIP - however, the chan_sccp driver is compatible with the sip protocol on these phones - I did a quick search on the internet for the SCCP firmware of the Cisco CP 8841 and found nothing, just sip firmwares.
It seems that in this thread the phone was unable to work with sccp_manager, but I can’t tell if it was using the develop or stable version, it’s worth testing now with develop.
As there is support and an “official” listing of these phones in the manager, I believe it is possible to make them work