Tempo version 11.000 is a substantial revsion of the program. Improvements include a new, friendlier input file format, better astrometric algorithms, and a new binary model. ... Ephemeris: . ... A new free-format input file format has been added: . ... Final parameters are output in a file with the same format as the input files. ... Old-style files with fixed-format headers may still be used (`-o' command-line option). ... They are still allowed in input files for backwards compatability. ...