We have a file format, in which we are writing the format version in the header along with some other information. Initially some information is written into the file then followed by the version information. After that, the file data will be written. Now the version is "4.0.2". I would like to introduce a flag in the version for a specific task. In other words, I would like to read the file and if it is "4.0.2", then I would like to make it "4.0.3" or "4.0.2A"
How do I do it without disturbing the file format.