Can't install Thunderbird Version 153

<blockquote> I believe I downloaded 153, but I don't where to find it. </blockquote> In the Download folder? What did you download in the first place - The 153.0 ESR or the 153.0 Release version? And to which version do you want to update to? See https://support.mozilla.org/kb/thunderbird-esr https://support.mozilla.org/kb/thunderbird-release <blockquote> One page states, "Manual upgrade to 153 is now enabled via Help > About" </blockquote> Upgrading from which version? You'd need to provide more context. Also a link would help. <blockquote> ... but when I go to Help > About, all I see is the current version and the statement that it is up to date. </blockquote> As per the information you provided you're on TB 140.13.0esr. That is indeed the latest version of the 140 ESR update channel. The ESR version will have a three cycle (at least 12 weeks) overlap between the time of a new release (153.0esr) and the end-of-life of the previous release (140.xesr). After that you'll be automatically upgraded to the 153.xesr series, and you'd remain on the ESR update channel. <blockquote> The recommendation on one page regarding 153 is to switch from Release to ESR, </blockquote> You're still on the ESR update channel. So that "recommendation" sounds silly to me. You need to decide what '''you''' want, and not follow some random, and out of context "recommendations".