The fix for issue 72 did not stick, unfortunately, so I backed it out and replaced it with additional debugging code (thus, there is also a Debug version). Other than completing the rest of the relevant security updates, there are no other changes relative to the FPR3 beta. As usual expect this to go live tomorrow night sometime Pacific.
For FPR4, I have another large AltiVec upgrade in mind, and I would like to take a first pass at CSS Grid support and maybe also WOFF2 updates. In addition, because of the impending release of Firefox 57 "Judgment Day for XUL" this will be the first release of TenFourFox to have the "Get Add-ons" tab removed, since the Mozilla-specific pages will be hawking WebExtensions. You can still install old-style XUL addons compatible with the underlying Gecko 45 infrastructure; they'll just be something you have to separately download from AMO or whatever. While I might reintroduce this tab in the future, right now I don't have enough time to maintain a full-service legacy add-on site myself. However, if this is something Someone(tm) wants to work on and they can meet the technical requirements (and make a commitment to hosting it for an indefinite period), we can talk about it and see if you're the right fit for our community. Open a ticket on Github if you're that person.