Depending on which specific production your file contains, here are reviews for the most common versions:
This German-Swiss production is widely considered one of the most faithful and visually stunning adaptations. Heidy (1) mp4
If your file is an "MP4" of this recent release, be aware it is a "Swissploitation" action-comedy. Depending on which specific production your file contains,
There is a lesser-known horror film by the same name that features a haunted doll. Heidy (1) mp4
Heidi (2015) - IMDb
: According to PopHorror , this is a "slow burn" low-budget film that works well for fans of the found footage genre but may feel "padded" at times. Mad Heidi (2022)