升级到 MovableType 8.4.2， 无需赘述，下载一个 24M 的压缩包，解压缩，上传到安装目录，覆盖旧的文件。
然后登陆到后台，就直接完成升级 了。

虽然没有什么可以特别，还是介绍一下更新信息。

New and improved features

Updated Smarty from 4.5.3 to 4.5.5 (MTC-29974)
Updated MTBlockEditor to version 1.2.5
Updated MFA (Multi-Factor Authentication) plugin to version 1.0.5
Added support for MySQL caching_sha2_password authentication (MTC-29715)
Improved the response time of the admin screen by revising the processing of MT::Permission (MTC-29836)

Resolved issues

Fixed an issue where line breaks were not converted to
elements when pasting multi-line text in TinyMCE6 (MTC-30072)
Removed unnecessary files included in the package (MTC-30173)
Fixed an issue where inserting images in the old block editor caused an error when the width of thumbnails was specified (MTC-29967)
Fixed an issue where the user-specific archives of ContentType were not always fully rebuilt (MTC-29907)
Removed the use of the deprecated window.unload event in the Chrome browser (MTC-29851)
Fixed timing to call listReady event from Svelte on List view (MTC-29915)
Fixed to show confirm dialog after add/remove line on Table ContentField with browser backwording (MTC-29965)
Fixed to remove the filter item of username at List view with Svelte (MTC-29928)
Fixed to set a parameter to input field with filter_key on List view (MTC-29925)
Fixed the setting add / remove rows and lines swapped on Edit ContentType (MTC-29839)
Fixed to complete the process of mt-search.cgi with mass request parameters (MTC-29943)
Fixed performance issues of processing parameters of Data API (MTC-29962)
Fixed performance issues of processing parameters of Comment (MTC-29955)
Improve performance of mt-search.cgi with specific parameters (MTC-29961)
Fixed performance issues of processing parameters of mt-search.cgi (MTC-29953)

Updates JavaScript Libraries

Update a-table.js from 1.5.9 to 1.5.10 (MTC-29854)

Security fixes and improvements

Update TinyMCE 6 from 6.8.4 to 6.8.5 in the TinyMCE6 plugin (MTC-29922)
Fixed Cross Site Scripting (XSS) of object embedding in MT Blockeditor using TinyMCE6 Plugin (CVE-2025-24841, MTC-29997)
Fixed Cross Site Scripting (XSS) on the page of Edit a Custom Block in MT Blockeditor (CVE-2025-22888, MTC-29937)
Fixed Cross Site Scripting (XSS) on Edit user page (CVE-2025-25054, MTC-30057)