SRSv2 3.1.113.0 has been available as an automatic update to all devices for about one week now. 3.1.115.0 has been available over the last 48 hours.
3.1.113.0 Release Notes are as follows:
...
Published Jun 21, 2018
Version 1.0
Blog Post
its in the SRS documentation v2 webpages:
Custom Theme Images
The custom theme image file must be placed in C:\Users\Skype\AppData\Local\Packages\Microsoft.SkypeRoomSystem_8wekyb3d8bbwe\LocalState, just enter the file name and extension in the <CustomThemeImageUrl> variable.
The image file should be exactly 3840X1080 pixels and must be one of the following file formats: jpg, jpeg, png and bmp. If your organization wants a custom image, a graphic designer will find our https://go.microsoft.com/fwlink/?linkid=870441 useful. It contains further detail on where to place various elements in a theme image and what areas appear on consoles and displays.
The XML configuration file must be updated at device startup to recognize the theme image. Once the new XML file is processed and deleted, the theme graphic file will be deleted from the directory.