My simplex came with 2.68 November 2019..In April 2020 I upgraded to 2.76..After 10 minutes of use i noticed a drastic difference from v 2.68...It was way more erratic and loose and the tones lost that bird chirp type quality and now sounded more like beeps.....I was like WTH...Then a couple days later i upgraded again to 2.77...That's when my computer craped out on me and i thought i lost my original 2.68 file forever..So i was forced to stay with 2.77 for the next 8 months or so...Then 2.78 came out and i upgraded again...The whole time i missed how v2.68 was...It's tight and fast and unlike any of the newer versions in my opinion...Yes the newer versions are deeper but from 2.76 and up were so erratic i found my self backing the sensitivity way down anyways....With 2.68 i could run it on 100% almost all of the time..I ended up getting my 2.68 file off the old hard drive and reverted back to it...The second i turned the simplex on with my original 2.68 file i could tell it was back to how i remember it...Tight and fast with the chirpy tones...Even the recovery speed in field mode was set faster on the older versions...These are all the versions 2.62,2.67,2.68,2.76,2.77 and 2.78 JUST REMEMBER IF YOUR SIMPLEX DIDN'T COME WITH V2.62,2.67 OR 2.68 YOU CAN NOT REVERT TO THOSE VERSION OR YOU WILL BREAK YOUR MACHINE...According to Nokta..