Why do we have versions in API .NET Client library.

[Mounica Chitte]

What is the reason behind maintaining different versions of Client library? Every time a release is being made to Library, is it mandate that we need to make code changes in our Application?

[Thanet Knack Praneenararat (AdWords API Team)]

Hi Mounica,

Generally speaking, for all Google ads client libraries, we make a new release when 

• a new AdWords API version, e.g., v201605, has been released.
• an old AdWords API version will be sunset.
• a new feature is released during the above version boundary.
• a bug is fixed.

You can check the purpose of each lib release in the ChangeLog file in GitHub repository.

For a specific issue about .NET client lib, I recommend to ask in the issue section of the repository.

There will be the lib owner answering your question more specifically.

Every time a release is being made to Library, is it mandate that we need to make code changes in our Application?

You don't always need to do so.

But I recommend to use the latest version as soon as possible, so that you can avoid any known bugs and can use the latest available features. 

Best,

Thanet, AdWords API Team