angular-bootstrap-affix | Affix directive for AngularJS | Plugin library

Only updating your angular package will work locally, but when a new project needs to be setup and you want to install your dependencies you'll run into this problem any ways. I suggest you setup your dependencies how you want them and make sure you don't allow deviations to version you don't want to get installed. I'll add some info on how interpret the version numbers.

Using bower update will update only that package to the version listed in the bower.json

Assume a version number like this: 1.5.0. Each number has a mean, 1 is the major version, 5 is the minor version and 0 is the patch number. So like this major.minor.patch

A caret (^) means you can't change major version, but you can change minor and patch version. So ^1.5.0 can range from 1.5.0 until but no including 2.0.0. So in your cause because you had ^1.5.0, Angular will update to the latest non-major version change which is 1.6.3

A tilde (~) means only the patch version change (or minor version if patch isn't specified in the version)

Read more about it here: semver