In the office, we generally work with a shared SQL database (Oracle). However, we are often offline and use our library as a .bib file (read and write). What is the easiest way to to reliably synchronize two libraries (file to file or shared SQL database to file)?
You could use a git-repository (on a server or a git hosting website, such as GitHub) and then push and pull or use a pull-request based workflow. Git is a version control system, so that means you can see exactly who changed what, when and it provides a way to deal with merge conflicts.