When there are changes to your BIM model or your Master schedule, there may be inaccuracies between your model and schedule. For example, your original BIM model has a column that is linked to an activity. Say this column is shifted to a new location, or removed, and the model is saved, it means that the model has a new version. At such, you will be able to load a new version, or reload the old one through the Version window in LPD + BIM.

Versions can be found on the top tool bar. 

Click Versions to open the versions window. This window will show the entire history of versions for the model that is currently loaded in LPD + BIM.
Click on any version that you wish to load, and click Load Version.
Click Yes to confirm your action, and the model will be changed to the chosen version.

When a new version is loaded, and there are now missing activities or BIM elements compared to the old version, you will have broken links in your plan. These broken links will be automatically detected by LPD + BIM, and notify you in the Linking Mode. To learn how to fix those broken and missing links, please read this article.