SeaMonkey support for banking sites and also for NetFlix?

[MichelPM]

I am a Mac OS X 10.6.8 and 10.8.5 user who can't upgrade past these version for software and software update finacial reasons.
I have tried SeaMonley, but many banking sites say this is an unsupported browser.
Also, similarly, does SeaMonkey support the Microsoft Silverlight Mac OS plugin for Netflix to work?
I am trying to transition off of Firefox because FireFox 48.0.2 is not as secure and many of my newer FF plugins no longer work under Firefox's ESR 45 release version as I suspect that that version of FF is simply too far back for many of my extensions and plugins to to work.
I use a YouTube download plug in, Microsoft Silverlight and about 6 other helpful and useful plugins and extensions that I use everyday.
The three things preventing me from using this web browser and recommending this to others is the banking support issues, Microsoft Silverlight not working with SeaMonkey, so I can no longer watch and use my Netflix subscription and my YouTube download extensions/plugins.
And, I just discovered that my Add Block plugin doesn't apoear to be working, either.
Will SeaMonkey step up to take Firefox's place for OS X 10.6-10.8 users in terms of complete browser support and functionalities?

Thank you for your responses and replies, in advance.

[James]

Plugins like Flash Player, Java, Silverlight etc are not Firefox or Se3aMonkey version specific.

Extensions are made version specific by the author though however. If the latest extension update does not work with say the Firefox 45.0 ESR Release branch then just check the version history of extension at addons.mozilla.org as the previous version may work.

Not sure which Youtube download Extension you are referring to as some of them are pretty old.

Firefox Releases no longer supports the old Mac OSX 10.6, 10.7, 10.8 as of Firefox 49.0 and later as the only option besides updating to OSX 10.9 or later is to use Firefox 45.0 ESR. https://support.mozilla.org/en-US/kb/firefox-osx

Not sure what the SeaMonkey community plans for OSX 10.6, 10.7, 10.8 support as SeaMonkey 2.46 Release will on same Gecko 49.0 as Firefox 49.0

[frg]

>> Not sure what the SeaMonkey community plans for OSX 10.6, 10.7, 10.8 support as SeaMonkey 2.46 Release will on same Gecko 49.0 as Firefox 49.0

Unfortunately non at the time. No ESR 2.42 is planned and it would also be only a short time solution because ESR 52 is on the horizon. Only an ESR 2.49 based on Gecko 52 is currently on the radar to extend Windows XP and Vista support.

FRG

[therube]

many banking sites say this is an unsupported browser

Which?
(And tell them they're wrong.)

FireFox 48.0.2 is not as secure

Not as secure as what, FF 49?

many of my newer FF plugins no longer work under Firefox's ESR 45 release

Plugins or Extensions?
Does FF 45 ESR still afford the [extension] "override"?

Microsoft Silverlight not working with SeaMonkey

Don't really know anything about Silverlight, but I'd expect that it would work with SeaMonkey?
What version of Silverlight do you have?
(Very possible that an outdated version is blocked, blocklist.xml.)
What does about:plugins show?
What does Addons Manager -> Plugins show?

my Add Block plugin doesn't apoear to be working, either

And just what is your adbock extension?
Both Adblock Plus & uBlock should be working.