Version 0.58 took the longer Experimental period concept and ran with it. The timing was good for such a shift as well, since 0.58 was an update focusing on back end changes and mechanics rather than new content. It was the first update in a long while to not include any map updates, further emphasizing that focus.
A load of new “things” made their way into the game like world containers, full availability of barrels, the car tent, and the UMP45. The vehicle repair mechanic finally began working its way in with tire repair, batteries, and plugs now being necessary to operate the V3S. Fishing was expanded with the addition of the Mackerel, and it became possible to use the indoor fireplaces of many houses.
0.58 included a new inventory screen for those opting into the use of the New UI, and persistence saw major changes as well.
The Experimental branch was relied upon heavily in non-standard ways during 0.58. It included a short-lived pair of servers configured for extreme rainy weather, and an eventual hotfix release for performance issues related to persistence was tested by by community members creating massive camps together.
-Initial Experimental Release: Jul. 1, 2015
-Initial Stable Release: Aug. 26, 2015
-Experimental builds: 15
-Time spent on Experimental: 56 days (3 days for hotfix)
-Hotfix(es): Sep. 14, 2015
For a look at what the extreme weather looked like, have a look at this album: http://imgur.com/a/feGuA