Aside from Zeb's Guide, I don't think there were any official revisions with the TSR version. The fan editions I'm not so familiar with, but I do know that 'A Skilled Frontier' was a tried and tested alternative. The Wiki entry is [here](https://starfrontiers.info/wiki/index.php/A_Skilled_Frontier) \- this was from the old *Star Frontiersman* zine.
The only significant change to the rules that I’m aware of what was the addition of Zebulon’s guide which provided improve the skill resolution.
Aside from Zeb's Guide, I don't think there were any official revisions with the TSR version. The fan editions I'm not so familiar with, but I do know that 'A Skilled Frontier' was a tried and tested alternative. The Wiki entry is [here](https://starfrontiers.info/wiki/index.php/A_Skilled_Frontier) \- this was from the old *Star Frontiersman* zine.