A workforce management software has complex GUI (for example values in a page depends on the status (closed or open) of other pages). Only latest and near past development has test coverage. During our last release, we received lots of bugs from customer in-spite of 2 weeks of testing Sprint. We don't have dedicated test team. The developers does the unit test and User acceptance test. Every day triggers automated regression test.
I am afraid the developers are not testing the entire workflow because its time consuming also not able to automate it because of its complexity. Any suggestions? The legacy code (15 years of development) has less code coverage. How can I improve quality?
Note: Now not possible to hire testers to have independent test team.