January 25, 2018

# How do software version numbers work?

### OVERVIEW

Software Version numbers are everywhere when we deal with software so its worth it to take a little time to understand their semantics when we start out. Lets take a look at two simple version numbers.

##### EXAMPLES

1.2.3

1.2.18

### HOW TO READ VERSION NUMBERS

Intuitively you might think that 1.2.3 is a higher version number than 1.2.18 because mathematically it is.

However, when dealing with version numbers we have to pay attention to number of digits in the number after the last dot.

The sequence of version numbers from 1.2.3 to 1.2.18 looks like this

1.2.3, 1.2.4, 1.2.5, …, 1.2.9, 1.2.10, 1.2.12, 1.2.13, …,1.2.18

The first digit is called the major version, the second digits is the minor version, and the last digit is for revisions.

When that first digit changes is when you can expect major changes and need to possibly get ready for a significant refactoring of your code.

**REFERENCES**