Olimexino-328 temperature range

[PiAn]

Hi all,
I'm seeking the possibility to use the-328 for an antartica-based scientific equipment watchdog. I need -40°C. It is specified for -25°C but a quick look at all components used in shows that they are all qualified for -40°C, with maybe the exception of the 74vhc08d (NXP is -40°C but sourcing can change).
Where does this -25°C restriction come from ?
Would it eventually concern the LiPo battery, meaning that the card could be used, but without the battery ?
Thanks for support,
PiAn