Now that modern browsers are in widespread use, we should probably look at upgrading to Bootstrap 4. At the same time, it should modernize the theme's appearance a little.
I could look into opening a pull request to migrate to Bootstrap 4 if this is desired. This would probably have to be released in a semver-major release like 4.0.0, since some user-made customizations might break with this.
Now that modern browsers are in widespread use, we should probably look at upgrading to Bootstrap 4. At the same time, it should modernize the theme's appearance a little.
I could look into opening a pull request to migrate to Bootstrap 4 if this is desired. This would probably have to be released in a semver-major release like 4.0.0, since some user-made customizations might break with this.