There are some changes to the 88 and X5 from 11th January. Details from North Somerset Council here.
The main changes for Portishead are that First X5 will run via the M5 beyond Clevedon, making it quicker to get to Weston-super-Mare. Some journeys are also extended beyond Cribbs Causeway to Bristol Parkway railway station.
Carmel 88 is being extended beyond Clevedon to Yatton to replace the diverted X5.
I'll post the new timetables here as soon as they have been published.