There is also the problem that the formatting syntax is actually slightly different between old.reddit and new reddit, causing a number of broken messages when browsing with the old.reddit.

I absolutely detest that, specially since they have put a giant loginwall in the mobile version of the new reddit which basically forces me to use the old.reddit. These practices are basically what I expect from a shady website, not one of the most popular ones. Reddit is really detestable and I wish we could do something to stop it from acquiring users.

Be careful with browser extensions. The edge old reddit redirect extension was malware and because they autoupdate your safety is dependent on the extension author refusing near-daily offers to sell out.

https://news.ycombinator.com/item?id=27305638

FYI: On Firefox it's setting dependent and the UX lets you easily decide if you want to use the global setting or set it specific for that extension.