| 2025-12-28 23:08:22 | ipggi | Added SFN Software as a subgroup of Underground Software Inc. |
| 2025-12-20 22:15:54 | ipggi | Edited notes |
| 2025-12-20 22:02:51 | ipggi | Added link https://csdb.dk/group/?id=3409 |
| 2025-12-20 22:02:35 | ipggi | Edited nick 'Underground Software Inc.': changed abbreviation to 'USI'; changed differentiator to 'c64' |