The new X14/15/18 timetables now available on Bustimes/Arriva's website. From what I could make out Monday-Friday changes are:

X14:
06:40 from Morpeth to Thropton will run 5 minutes later throughout
07:34 from Thropton to Newcastle will run 5 minutes later throughout
13:00 from Morpeth to Thropton withdrawn (12:23 NCL to Morpeth still runs)
13:54 from Thropton to Morpeth withdrawn (14:43 from Morpeth to NCL still runs)
15:28 from Newcastle to Thropton will run 5 minutes earlier throughout
17:09 from Thropton to Newcastle will run 5 minutes earlier to Morpeth

X15:
07:43 will now depart 10 minutes later from Alnwick and 5 minutes later from Morpeth

X18:
15:13 from Newcastle will run 5 minutes earlier

58:
Unless another operator's got the contract and yet to register on VOSA, seemingly withdrawn without replacement.