As usual in Service-Oriented Architectures such as CIL/CIS, the client and server versions are rather loosely coupled. That is: there is not a 1:1 relationship between the CIL and CIS versions you can use together.
On the other hand, you also cannot expect any CIL version to be 100% compatible with any CIS version. In general, backwards compatibility can be expected (i.e. an older CIL version should work against a newer CIS), but forward compatibility (i.e. using a newer CIL version against an older CIS) is trickier.
This answer is intentionally vague; it makes sense to check with Customer Support if you intent to use two quite different versions of CIL and CIS.
Regarding the versioning scheme used for CD NuGet packages: this is
Note that the patch/SP/CU version and build number are combined into the third part of the semantic version number. Also note that the patch/SP/CU number 0 is not explicit in the third digit. So:
11.0.1055 is actually
11.0.1097 is actually
11.0.11019 is actually
If there are multiple builds for a given major/minor/patch version, this means that hotfixes were released for that version. The specific version you're wondering about is a recent hotfix for