I got The Simplex in November 2019 so it had 2.68 on it...I upgraded to 2.76 then 2.77 in April 2020..Then up graded to 2.78 in December 2020...After all those versions i felt like the original 2.68 was the best..I successfully downgraded to 2.68 in Jan 2021 and the detector is fine..Good luck with yours..