Further updates have been made after 1988, but nothing that breaks 1988 implementations. Details of the standards involved can be found in the standards list on this document's webserver. This depends on what you are asking for. The issue of FTPing standards is painful, to say the least. ISO documents cannot in general be put online.
Some organizations also provide subscription services and provide copies of the standards.
Please contact him if you have additional interesting files. A lot of variants exist with more or less the same scheme. Often these implementations have a X.25 or a transport level interface with manufacturers supplied lower layers. In the case of transport-level, X.400 is thus able to run over CLNS as long as this is supported under the Tli or XTi. Finally, many X.400 implementations for PCs or Mac have been developped to use what exists in the PC arena such as PC-NFS, NETBios, X.32 or even dialup over modems.