On desktop LCD the new theme has low contrast and too large a line spacing, making reading version history difficult.
To fix it, I use the "Custom Style Script" add-on to Firefox (I use FF V.52.6.0 ESR). It allows you to inject custom CSS to any site. That add-on supposed to be also available for Chrome.

I use it to inject the following CSS to the winscp.net site. This is the custom code I use:

body {background-color: white; color: black; font-family: Arial; font-weight: 500; line-height: normal}

Now the history list, as well as most other pages, are readable :-)

Sorry, but that's not possible. We need to eventually discard a code for the old design.

I would donate to be able to set the cookie "winscp_newdesign" to 0 again. Is it being forced to 1 now.

Thanks for your feedback.
I'm sorry that you do not like it. But we do.

Loved the old theme. Why the change?
This one seems much worse for the eyes. Bad contrast, excessive item's spacing (bad for desktop browsers) etc...