IHC-200_wifi different module versions

hi, we have 12 IHC-200-wifi controllers we have purchased over the last year and 6 of them from last year purchases no longer automatically get detected to connect to the any app’s while the other newer 6 do. the difference seems to be the older no longer working devices are on
main module: v3.1.4
MCU module: v1.0.0
while the newer one that are working seem to be on
main module: v2.5.2
MCU module: v1.0.3
any advice or guidance to get them all running on main module: v2.5.2
MCU module: v1.0.3 would be great

Just to confirm, are you using the latest version of the INKBIRD APP?
None of the 6 IHC-200-WIFI purchased last year can connect to INKBIRD APP?
If you long press the up button on the old IHC-200-WIFI, does its WIFI indicator flash?
Can it connect to INKBIRD APP if using the slow flash mode?
Please make sure that the router does not have a limit on the number of connected devices.

i will bring home the devices that are not working home tomorrow and go through these steps to confirm but as i recall they where not connecting to the inkbird app.
yes only devices that where purchased last year are not connecting.
going into connect mode works, i have connected the 6 that were not working to smart life app through > small home appliance > humidifier(wi-fi)
but my other 6 devices get auto detected by inkbird or smart life app’s no problems…
i am connecting them to a mesh system with a 2.4 GHz network that can support 150 devices.
the only difference seems to be the firmware… i have used smart life to connect to tuya iot platform to try and flash them back to main module: v2.5.2 and MCU module: v1.0.3 but i have not found a way to do this myself…

Please understand that the Smart life app is an app from another company.
If all 6 IHC-200-WIFI cannot connect to INKBIRD APP, our engineer will further troubleshoot the problem.
If they can connect to INKBIRD APP but cannot connect to Smart life app, the engineer will try to communicate with the engineer of Smart life app, but this function needs to be optimised by the engineer of Smart life app.