# Custom ProjectionsSince Input 0.8.0
You can read more about Map Projections and Coordinate Reference Systems in this extended article.
# Using custom PROJ
When Mergin Maps Input is launched, it searches for
<project folder>/proj for custom PROJ datum shifts files in all available projects on the disk. These shift files can be then used in all projects for custom PROJ datum shift.
If you want to use your custom PROJ datum shifts, copy them to the folder
<project folder>/proj to correctly render your QGIS project on Mergin Maps Input. Note that one the project is firstly downloaded to Mergin Maps Input, you have to restart Mergin Maps Input to load your custom datum shifts.
We recommend to use Mergin service to transfer the project with the required proj resources to your mobile device.