This new feature only works on MTEXT but that should be fine for most people.
With AutoCAD 2016 Mtext can now have a text frame that dynamically sizes itself as you edit the text.
Simply select the MTEXT
In the Properties palette, under the “Text” area, notice the new “Text frame” option and change it from “No” to “Yes”
Note: the size of the text frame is determined by the size of the background mask offset factor. Which brings another great possibility – combining the new TEXT FRAME option with a background mask.
AutoCAD Tips 
Background mask existed in 2014 for sure.
I like this feature just because of the framing. That definitely improves the readability in some situations with certain patterns.
WOW so amazing, such innovation …., but can you change the color of the frame without changing the color of the text ?
Does Autodesk need 50 more years to implemented this little detail? I mean, it was quite obvious that people will want to change the color of ONLY the frame.
Unfortunately, There isn’t a way to do this
To change frame color: Double click on mtext to open text editor, right click in text editor, click “select all”, on the text editor ribbon click on the color drop down and change the setting from “by layer” to the color of the text you want.
Click outside the text editor, click on the mtext once to select it, Go to properties, change text frame to yes, then go to color and change the color from by layer, block etc to the frame color you want.
The border will now have a separate color from the text.
Unfortunately, have to do this for every mtext item individually. Hopefully the folks at Autodesk will update this at some point. If one has mtext with colored background with white text and the frame is white, it will not show the frame.
I also see a product on the Autodesk app store for $1.99:
https://apps.autodesk.com/ACD/en/Detail/Index?id=2133801928521397582&appLang=en&os=Win32_64