If you’re using Siemens TIA Portal with Version Control, via Copia and/or the Version Control Interface, you may have run into a merge conflict; with multiple engineers working on the same parts of the same project at the same time, you may run into a situation where two engineers have made changes to a project that directly conflict with one another.
Copia provides a powerful merge tool for Step7 projects from TIA Portal v15.1-v17 to assist with this, letting you pick which version belongs in the final product for each individual conflict.