To add to this: Usually, going up a version number (like from 0.7.x to 0.8) is just used to signify a major update, and the following minor updates will be appended to that (so 0.8 will become 0.8.x). Most of the following updates usually revolve around fixing/improving upon the new stuff from the last major update, until another new major update comes and they add another number.
This continues until the game is finished. You could end up with "v0.27.36" for instance. The big "1.0" means initial full commercial release. Then it follows the same pattern "1.0.1 -> 1.2.5 etc"
Of course, the exact format is dependent on the dev.
