Some spreadsheet editors like NeoOffice or Calc still support Navy DIF spreadsheet format and thus could export STC spreadsheet templates to DIF format. However, templates generally contain no actual data, so the purposes of this conversion would be a mystery.
Convert OpenOffice.org Calc spreadsheet template to Navy DIF spreadsheet.
We have found 3 software records in our database eligible for .stc to .dif file format conversion.
Apple macOS / Mac OS X software - convert stc to dif on OS X
A full-featured set of office applications for Mac OS X
Convert from stc file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned stc to dif. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Multiplatform software - convert stc to dif on any platform
Full-featured spreadsheet tool from LibreOffice suite
Spreadsheet program from OpenOffice.org productivity suite