--- title: "Firefox 153 contains itself while Thunderbird 153 fixes almost everything" url: https://daily.dev/posts/firefox-153-contains-itself-while-thunderbird-153-fixes-almost-everything-cvjcxqopd source_url: https://www.theregister.com/software/2026/07/23/firefox-153-contains-itself-while-thunderbird-153-fixes-almost-everything/5276390 type: article source: "The Register" published: 2026-08-06T10:37:21.276Z updated: 2026-08-06T10:40:18.160Z tags: ["firefox", "mozilla"] reading_time: 3 upvotes: 0 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Firefox 153 contains itself while Thunderbird 153 fixes almost everything **[The Register](https://daily.dev/sources/theregister)** · 3 min read · 0 upvotes · 0 comments ## Summary Firefox 153 introduces a new feature that walls off online identities, keeping different browsing contexts isolated from each other. Thunderbird 153, released by MZLA, focuses heavily on bug fixes, addressing a large number of issues in the email client. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Firefox and Thunderbird 144 are here](https://daily.dev/posts/firefox-and-thunderbird-144-are-here-o7hnacejw) · The Register · 0 upvotes · 0 comments - [Thunderbird 143 Release Delivers Mailbag Full of Fixes](https://daily.dev/posts/thunderbird-143-release-delivers-mailbag-full-of-fixes-d3p1hbkit) · omg\! ubuntu\! · 0 upvotes · 0 comments --- Tags: [#firefox](https://daily.dev/tags/firefox), [#mozilla](https://daily.dev/tags/mozilla) [View this post on daily.dev](https://daily.dev/posts/firefox-153-contains-itself-while-thunderbird-153-fixes-almost-everything-cvjcxqopd)