Samsung Internet version 4.0 was released about two months ago, it brought several new features including but not limited to support for adblocking extensions and popup video player. The app has now been updated with support for older Galaxy devices and it finally brings these features to those devices. The full list of supported devices has been published on the app page in the Google Play Store.
Other features in Samsung Internet version 4.0 include a Secret Mode which cloaks browsing data, tight integration with Samsung Internet for Gear VR, ability to view online videos in a popup window to browse the web while playing videos, support for third-party content blockers and much more. Samsung Internet is available as a free download from the Google Play Store. It's compatible with devices like the Galaxy Note 3, the Galaxy S4 and others running Android 5.0 Lollipop and above.