SIMION 8.1.0 uses CODATA2010 constants (see Wikipedia:CODATA). This differs from the 8.0 manual.
In SIMION 6.0/7.0/8.0, the constants are CODATA1986 values. Dahl2000 notes “The physical constants used in version 6.0 and 7.0 are from the 74th edition of the CRC Handbook of Chemistry and Physics  Values of these physical constants (e.g. c, electron mass, and elementary charge) are defined to 8 or 9 significant place accuracy”. The 74th edition (1993-1994) uses CODATA1986, which were the latest CODATA values at that time. SIMION 8.0 also uses these constants.
NoteThis page is abridged from the full SIMION "Supplemental Documentation" (Help file). The following additional sections can be found in the full version of this page accessible via the "Help > Supplemental Documentation" menu in SIMION 8.1.1 or above:
- List of constants