Actually, I don’t have any inside information.
That said, the main work to obtain the M88 T-REX engine has already begun, since it must be available before 2030 for the first flights of the Rafale F5.
Furthermore, to convert a standard M88 into an M88 T-REX, only a few modules will need to be changed — I believe it’s around three modules, while the M88 has about 21 modules in total. The M88 was designed as a family of engines sharing the same core, with growth potential. The family was originally intended to cover roughly 7.5 tons to 11.5 tons maximum thrust.
Now, the technological step brought by T-REX basically shifts these capabilities upward by about 20%, while keeping the same overall dimensions and weight.
To replace the F414, we would need an engine in the 6-ton class (dry). With the T-REX technology on the current M-88 we can reach around 6 tons, and with afterburner we can obtain about 9 tons without any major redesign.
If we want around 10 tons with afterburner, we need to ingest a bit more air, meaning a slightly larger fan diameter. But we have margin here: the F414 fan diameter is about 89 cm, while the M88 is only about 69 cm. A fan diameter around 79 cm would already be more than sufficient.
So, in theory, it would be possible to create an engine with the final integration characteristics suitable for Tejas Mk2, even without the full T-REX technology at first. Such an “intermediate” engine could deliver around 5.5 / 8 tons (dry / afterburner), and later it could accept the three upgraded T-REX modules, bringing it up to around 6.5 / 10 tons.
It would also have the advantage of allowing early studies and tests for the integration of an M88-derivative into the Tejas Mk2.