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SeaMonkey (64-bit)

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SeaMonkey 2.53.15 (64-bit)

  -  41.38 MB  -  Open Source
Free Download

Security Status

Sometimes latest versions of the software can cause issues when installed on older devices or devices running an older version of the operating system.

Software makers usually fix these issues but it can take them some time. What you can do in the meantime is to download and install an older version of SeaMonkey 2.53.15 (64-bit).


For those interested in downloading the most recent release of SeaMonkey (64-bit) or reading our review, simply click here.


All old versions distributed on our website are completely virus-free and available for download at no cost.


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If you have any questions or ideas that you want to share with us - head over to our Contact page and let us know. We value your feedback!

Download SeaMonkey 2.53.15 (64-bit)

  • SeaMonkey 2.53.15 (64-bit) Screenshots

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    SeaMonkey 2.53.15 (64-bit) Screenshot 1
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  • SeaMonkey 2.53.15 (64-bit) Screenshot 4
  • SeaMonkey 2.53.15 (64-bit) Screenshot 5

What's new in this version:

- Microtasks and promises
- Implement queueMicrotask()bug 1480236.
- Remove old synchronous contentPrefService from the tree
- Remove remaining uses of 'general.useragent.locale'
- Migrate to intl.locale.requested.locale list from 'general.useragent.locale'
- Introduce a pref to store BCP47 locale list
- Remove synchronous certificate verification APIs from nsIX509CertDB
- Taskbar preview's favicon appears blank
- Call Imagelibs decodeImageAsyncWindows using a callback
- Remove PermissionsService from process Windows sandboxing code
- Security info dialog doesn't show cert status anymore
- Replace nsIPlatfromCharset in mailnews
- Replace use of nsMsgI18NFileSystemCharset() with NS_CopyUnicodeToNative/NS_CopyNativeToUnicode()
- Cater for Outlook's/Hotmail's 'Deleted' folder
- Make some filter methods scriptable
- Fix crash in nsMsgFilterAfterTheFact::ApplyFilter() caused by async reset of 'm_curFolder'
- Localize messages from nsIMsgFolder.logRuleHitFail()
- Add logging of message filter runs and actions
- Check that we got a non-null header before running a filter on it (and crashing)
- With CONDSTORE, eliminate unneeded flag fetches at startup
- Fix so custom tags (keywords) are visible to all users
- Improve handling of tags on shared folders
- Allow setting/resetting junk marking by user for yahoo/aol to stick
- Don't check subject if spellchecker is not ready
- Grammar issues in mailnews_account_settings.xhtml
- Remove use of nsIMemory
- Replace obsolete GetStringBundleService call in SeaMonkey
- SeaMonkey crashes on macOS Ventura 13.0
- Website Navigation Bar has stopped working
- SeaMonkey switch to fullscreen does not work on macOS Ventura 13.0
- Continue the switch from Python 2 to Python 3 in the build system
- Added support for clang 15 and macOS SDK 11.3
- Verified compatibility with Rust 1.65

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