No need to check the release notes. Here are the important features added to Google Tag Manager in the last months:

Google rolled out a feature to stay more organized. Folders are useful for splitting up a container into multiple smaller units. You could for instance create a folder called “Release v. 2.0” and put in all tags, triggers and variables you added in the new release of your container (yes they work like regular folders, you can throw in multiple types of items).

Though I think the feature is still underdeveloped, it’s the best you can use right now to organize containers with lots of tags.

You can find the feature under “Folders” in the left menu bar. There you can create new folders and add items (tags, triggers and variables) to your folder.

Once you create your folder, a “Folder” column will appear in the tags, triggers and variables windows. My main use case is to sort by folder and view the tags contained in the folders:

I also use folders for domain specific tags once either the numbers of domains or the number of tags within one domain grows.

Testing containers in GTM works great, you create tags and triggers and then hit the preview & debug button. However to see whether requests were actually sent to  Google Analytics, you need to turn on the “Use Debug Version” option you can now find under the “Advanced Configuration” in every Universal Analytics tag.

Lastly there is also Tag Sequencing. But Simo Ahava can tag sequencing explain that way better than I can.