It was with some surprise that I discovered recently that new encodings for ISO 8601 date/time types had been added to the X.691 PER encoding standard. The rumor for many years was that ASN.1 was finished and nothing new was going to be added. It therefore came as a pleasant surprise to see new capabilities introduced.
This particular new capability seems very logical. Date/time types are prime candidates for optimized encoding given the short numeric ranges used for the particular components. The new encodings rarely, if ever, take up more than 32 bits, and they are straight-forward to understand. This adds even more capability and compactness to ASN.1 PER, which IMHO is still the most useful compact standardized binary encoding around. Recent attempts to come up with binary encodings for XML have the feel of trying to fit a square peg into a round hole.
As to our implementation of these new rules, they will be in ASN1C v6.3.1 which will be released in a week or two. Support in the ASN1VE Viewer/Editor will most likely not occur until this summer.
So well done ITU-T! My only request in the future is to please provide some kind of notification system for standards updates so that we are not caught completely off guard.