[lubuntu] adobe flash blocking prompts

I use Firefox on Lubuntu. Every time I land on a webpage that uses flash, Firefox blocks Flash because it's outdated / vulnerable. So I click through the prompts to enable Flash for that particular domain 'Allow and remember'. But, Firefox never does seem to remember and even for the same page / domain, asks me the same question again and again.

I tried to update Flash but didn't seem to be able to.

I can use Flash ok, but I have to reauthorise the admittedly unsafe / outdated version every single time.

What can I do to make Flash enabled web content work safely and without continual prompting.. is there any kind of opensource alteative out there or is the only option, to just keep on individually allowing every piece of Flash content & accept the usage of an old vulnerable version?

- - , .
.