Have there been revisions to the rules of Catan?
I think this is worth an explicit answer, but I agree with @ConMan and @Gendolkari in the comments of the question and @JoeW's answer.

Yes, there have been many minor changes in the rules.

No, you have never been restricted from taking other actions following a roll of a 7. You always get your turn as normal.

One possible source of confusion in this area is the limit on playing 1 development card per turn. Using a knight before your roll in many ways replicates the actions of rolling a 7 (excluding the hand size based card loss). It is possible these two things have been conflated in a house rule.

Annotated Rules From the linked annotated Rules from 1st Edition.


  (3) After discarding occurs, you also steal 1 Resource Card at random from a player who has a settlement or city adjacent to this new hex. The player who is robbed holds his Resource Card hand face down. You then take 1 at random. If there are 2 or more players with buildings there, you may choose from which one to steal. 
  The robber must be moved. You may not choose to leave the robber in the same
  hex. After moving the robber, your turn continues with the trade phase.