# Project History and Versions

Each time someone synchronises the project from a mobile device or from QGIS through Mergin Maps QGIS plugin, a new project version will be created. Thus, it is possible to see the details of the changes made in Mergin Maps project by different users or devices.

On app.merginmaps.com, you can view what files have been added or removed. If you use GeoPackage for your survey, you can also see the list of the features which have been added, deleted or updated.

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Great tools to inspect the project history and compare changes between project versions can be found in the QGIS plugin:

  • use Create report to get an overview of changes for a range of project versions.
  • use Create diff to extract changes made between two versions of a layer

# Project history and advanced changelog

To see the project history:

  1. Log in app.merginmaps.com and go to your project

  2. Navigate to the History tab.

    Here you can find all available versions of the project. These versions can be downloaded to your computer which can be helpful if you need to create a backup or restore previous version of the project.

    Mergin Maps project history web

  3. Click on a version to see more details about what was changed.

    You can inspect the list of added, edited and removed files.

    Overview of changes made in a project in the dashboard

  4. For GeoPackage layers, there is an option to see even more. Click on Show advanced

    Show advanced changelog of a layer

  5. Now you can see the overview of feature changes in a specific layer across all attributes.

    Here, there are multiple changes in the trees layer. One feature (fid: 9) was added, one feature (fid: 6) was deleted.

    There are two modified features:

    • fid: 2 was moved to a new position
    • For fid: 8, the value of attribute species was changed

    Dashboard advanced changelog

# How to revert to an older version

You may find yourself in a situation where you want to revert to an older version of the project.

Local changes made in QGIS (changes that were not synchronised yet) can be reverted by using the Reset changes option in Project status.

To revert to an older version of a project (already synchronised to the cloud), follow these steps:

  1. Log in app.merginmaps.com and go to your project
  2. Navigate to the project history and find the version you want to use
  3. Download the project version to your computer. Open the project in QGIS to make sure it is the version you want to restore.

    TIP

    Our blog Downloading a previous version of your project (opens new window) contains detailed steps on how to download projects that are too large to be downloaded from the dashboard.

Now you have multiple options:

  • Package the downloaded project version as a new Mergin Maps project. You can keep both projects if needed or delete the one you don't need anymore.

  • Replace the specific files in your Mergin Maps project folder:

    1. Close QGIS

    2. Copy the QGIS project (.qgz), the data (.gpkg) or both from the downloaded older version and paste them to your current Mergin Maps project folder.

      Be careful when doing this!

      If you changed the data schema between your versions, this might be a bit tricky. By replacing the QGIS project file, you will revert the project settings, such as symbology, forms settings, relations, etc. By replacing the data files, you will get the content that was saved in the downloaded version of the project.

    3. Open the project in QGIS and check if you restored your project successfully. If needed, modify the project settings so that everything works as intended.

    4. If you are happy with the result, synchronise the changes. The restored version is now the current version of your project.