How to use labelImg again for annotation with previusly annotaed some classes.

[nmiraz]

At first we use labelImg for annotation and its work properly. no issue. but after few days later we want to add more class and side by side add more images according to new class with previously completed project. that time newly class name can replace the previous class name in class.txt. for this problem we have to do collect all them image with newly added and previous image in one place. then annotate again all of this images. then we can go for training.

have any solution for this type of problems. so that we can add any class and image in any time with previous project.
Thanks