Short update on all this.
HS-TGO is now retrofitted and returned to service.
The following registrations are 74R: HS-TGO, P, R, T W, X
Soon to become 74N: HS-TGY, Z, A, B, F, G
Remaining 744 which will leave fleet soon: HS-TGK, L, M, N,
Already converted to freighter: HS-TGJ, H
HS-TGJ cargo conversion has been completed. She's back at BKK already.
From the 74R, they're all inplace and flying daily.
From the remaining 744, all are still in the fleet and flying daily (according to flight data).
That is quite possible. She was at UTP for D-Check. She could then be converted to the new config (dubbed "74N") right afterward.
According to the Summer TPI, TG920/921 is scheduled to be operated by 74N starting 1 August. They need at least 2 aircrafts for that (preferably 3 aircrafts for operational consistency). Usually the first retrofitted aircraft will take longer to retrofit and re-certify (for the last retrofit, there was a delay of up to 3 month between first and second retrofit aircraft) so I think if they want to stick to the plan they should start with HS-TGY now.
From the future 74N, 5 are flying, and still not updated.
HS-TGY is still gone and not back in the fleet. Anyone knows what's happening?