Currently avoid overflying Iraq and Syria, also avoid flying through Ukraine. Most airlines route across Turkey to Alram (Iranian FIR boundary) and then South and or further East. Regarding the Gulf itself, you only need to know that you should call Iranian Air Defence on 127.8. 10 mins prior to entering Iranian airspace as a courtesy call giving basic details of your flight, point of departure, destination, flight level, squawking etc. All the ATC agencies around the Gulf are generally very good and will pass you onto the next ATC agency with the frequency given. Like normal operations, you should keep a listening watch on 121:5 box 2 so you can be called there incase you miss a radio call and get out of that agency's radio range.
J