I´ll try by heart, so some mistakes may happen...
Catalog 4 - same as EMDIR but programmable, offers R/S, SST and BST
Catalog 5 - same as ALMCAT but programmable, offers R/S, SST and BST
Catalog 6 - cat for key assignments, offers R/S, SST and BST
and clearing by [C] (or Shift [C]?) pressing
New X-functions:
Locating statistics registers: ËREG? (Ë for sigma)
Clear blocks of register contents by X: CLRGX (I think this is new, exclusive for CX)
Get key by X: GETKEYX (this one also)
New X-Memory functions:
Knowing free X-Mem space: EMROOM
Knowing fre space on an ASCII file: ASROOM (maybe ASCROOM, should try...)
Recalling data about a particular file: EMDIRX (returns file name in ALPHA, file size in X and makes it the current file)
Changing size of an ASCII/Data file: RESZFL (ERROR if used for program files)
I do not use often the time functions, but some new are:
CLALMA, CLALMX and (not sure) CLALMS or CLRALMS - allow selective alarm clearing, all programmable
RCLALM recalls some alarm data
and if I am not wrong, SWPT, that I have never used.
The major addition is the ED, or Text Editor, which was given a complete describing section.
If there is anything missing, forgive-me. The last point is some new terminology used in the CX literature, avoiding some sort of confusion.
Hope it helps.