Blogpost Version 2016-12-31
Additionally to the rather outdated “official” Release Notes here you find some more information concerning changes with SeaMonkey 2.46.
You need a Bugzilla-Account for the queries here in the blogpost. All queries without any liability
Mistakes in official Release Notes
- “The cursor may change … (bug 736811)” is WORKSFORME since 2014-11-27 (User NoOp told so on mozilla.dev.apps.seamonkey)
I submitted Bug 1325744 – 2.46 Release Notes “known issues” wrongly refers to bug 736811
I do not know which Firefox49 – features made it into SeaMonkey 2.46
A Bugzilla query shows SeaMonkey 2.46-specific RFE-Fixes.
More new features
Mozilla develover tools now are available in SeaMonkey (via ‘Tools – Web development …’). Some functions still no not work correctly, because those tools have been developed for Firefox, and adaption for SeaMonkey still is in progress.
SeaMonkey 2.45 already had the Lightning-calendar, because of issues with localization infrastructure Lightning will not be shipped with SeaMonkey 2.46. If you want to use Lightning, please download from AMO. Version 5.1b1 should work with SeaMonkey 2.46.
Some additional comments concerning new features:
Bug 1294432 – (SM245-RELNOTE) Create/Update 2.45 Release Notes
Bug 1302639 – (SM246-RELNOTE) Create/Update 2.46 Release Notes
- “The option ‘Ask me every time’ in the Cookies preferences had to be removed as the backend core support was removed (Bug 606655).”
- Bugs in SeaMonkey 2.39 … 2.40 what have been fixed for SeaMonkey 2.46.
- Bugs which have been fixed in Firefox and Bugs which have been fixed in Thunderbird since SeaMonkey2.40. Not all bugs in Firefox or Thunderbird do affect SeaMonkey, but also it is not sure that all fixes will work in SeaMonkey.
“Setting the default search engine in the Internet Search preferences has no effect (Bug 1265881). You can still change it from the side bar [F9].”
The “Known -Issues“- list is outdated, here an attempt for a more realistic overview.
Possible new bugs (“Regressions“)
- Possible new bugs in SeaMonkey — only those with Status New or Assigned already have been confirmed as real bugs
- Possible new bugs, caused by regressions in Firefox or in Thunderbird, which also might affect SeaMonkey.
You can find workarounds for new problems in the Wiki
Old and new bugs
A horribly long list, what does not consider that not all Thunderbird– and Firefox-bugs are relevant for SeaMonkey. And many of them are UNCONFIRMED or outdated (have been fixed in between).
SSE2-capable hardware is required for SeaMonkey 2.46 (at least for Windows). A symptom that your PC does not fulfill this requirement might be an error message during installation “… requires WIN XP SP2” although SP3 is installed. 
Pay attention: In (Mail- or HTML)-Composer ‘Rightclick → Languages → Download more dictionaries …‘ will lead to this page “Dictionaries & Language Packs” with a Link to Deutsches Sprachpaket für SeaMonkey 2.39. This language pack is for SeaMonkey version 2.39 and must not be installed for SeaMonkey 2.46. Probably the add-on-installer will reject installation – but you never know. And who uses the Add-On-Converter might be seduced to adapt the “Maximum Version” and to install the converted Language Pack (I have not tested yet whether that really would be possible). A Language pack with a version number not matching with SeaMonkey version number can cause serious problems, even make unusable a user profile.
All builds from download page are for 32 bit systems (as far as I know).
Windows builds will work on 32bit and 64bit systems
Linux 32bit builds will not run on 64bit systems “from the scratch”. You can try the 64bit build from contrib.
MAC: AFAIK Support for OSX 10.6 to 10.8 has became discontinued in 2.46 (nevertheless 2.46 will be recommended as update version for those OS, and it seems to work – you may try on your own risk. Backup your User Profile before you test, I read on mozilla.support.seamonkey (2.46 Automatically Updates, Breaks Mac OS 10.6.8) that this test might damage the User Profile).
And: Nothing we can do about it. Support for those OS version has been removed from the Gecko49 engine and Firefox 49, and so also from SeaMonkey.
See Bug 1257256 – State clearly that Linux builds in Downloads Table are for 32bit only
And please do not believe in truth of official System Requirements information and try SeaMonkey with Pentium 233 MHz 128 MB RAM, 50 MB of free HDD space 😉
Chatzilla & DOM inspector
Have been dropped from SeaMonkey 2.46 bundle because of localization infrastructure problems only for this Version. For Details see Bug 1231349 – L10n repacks broken on with SM 2.42 and newer.
If required please download these Add-Ons from AMO:
Catzilla works fine with SM 2.46. With an existing User Profile you might not observe that SeaMonkey 2.46 has been shipped without Chatzilla, because the existing CZ version still works.
DOM Inspector 188.8.131.52-signed due to AMO is only compatible until SeaMonkey 2.39.