Software versions aren't actually decimals, despite using a decimal point separator, so usually no. One of the most common schemes, "semantic versioning" is "major version . feature update . bug fix" and the number can go as high as necessary.
Typically:
* Any update to the right-most number is a "non-breaking change," which means everything should be compatible.
* Any increment to the middle number may be a feature update or a "breaking change," which means a change was made to the interface with other software. Some examples with Vocaloid would be requiring that voice banks be updated, due to a change in how it interacts with banks under the hood, or a change in how the VST interacts with a DAW or something that might change how a given project file sounds when rendered.
* The rightmost is usually a major rewrite.
You could have Vocaloid 6.997.2249