Hi,
Though I liked the older Outline theme, it was due to be replaced for some time now. I find that this current solution, though likely not unanimously, will improve the forum readability.
I'm planning to improve it a bit over time, when/if I have the time. One of the issues I have with it is that it may be too wide on larger screens, that could be fixed using a max-width setting for the containers.
If you should want to set the theme to the previous version, you can change it on the Layout options of your Profile area. If you do change, please write a comment below and vote in the poll (you can change the vote if you change your mind).
I have also installed a mobile specific theme that doesn't look all that nice, but it presents with good functionality. Nonetheless, Tapatalk continues to be the recommended solution for mobile devices. I'm expecting more browsing issues with this one, but it does have a "desktop" shortcut...