How and why ublock works that is up to their support to answer why it's not working. If you don't update there are chances sites block your firefox browser access and the CA are out of date. Since there is no OS specs no one can know what else to look for.

I asked about extension Ublock is only example .All my extension do not works due to Expiring Root Certificate in firefox .

How to fix it .How to manually install Root Certificate.There is any way fix this issue .?

I use windows 8 firefox 88

It's not expiring but you need to move to ESR firefox to use the browser and some Addon will not work because they don't work or run correctly on ESR firefox.

https://support.mozilla.org/en-US/kb/firefox-users-windows-7-8-and-81-moving-extended-support

I use .. firefox 88

That is the reason as explained in https://support.mozilla.org/en-US/kb/root-certificate-expiration

To not have your extensions be disabled you need Firefox 128 or later of for Windows 7, 8, 8.1 and macOS 10.12, 10.13, 10.14 OS users you need at minimum Firefox 115.13.0esr though Fx 115.21.0esr is the current.

https://archive.mozilla.org/pub/firefox/releases/115.21.0esr/win64/en-US/ other language folders at https://archive.mozilla.org/pub/firefox/releases/115.21.0esr/win64/

Or if you have 32-bit Windows 7 see https://archive.mozilla.org/pub/firefox/releases/115.21.0esr/win32/

It's not expiring but you need to move to ESR firefox to use the browser and some Addon will not work because they don't work or run correctly on ESR firefox.

The it is expiring as of March 14 and Extensions will not stop working due to using Firefox ESR in general.

This root certificate and March 14 date has been common knowledge here for a few months now.

Hi olek, there is no officially supported way to replace the baked in old certificate with a new one. I saw a long post on Reddit about unzipping a file, doing an edit, rezipping, etc., but followed by "do it at your own risk." I don't recommend that.

I'm sure there is a reason you haven't updated Firefox for four years. Was it related to the major appearance changes in Firefox 89 (Proton design)? There are style hacks to reshape the tabs if that is what has been holding you back. Let us know how we can help you make an updated version of Firefox more comfortable to use.

As a footnote, "xpinstall.signatures.required" only has an effect in the Extended Support Release and Developer Edition versions of Firefox (Add-on signing in Firefox), not a standard release like Firefox 88.

hi jscher2000 yes the reason was I do not like new browser appearance. That I do not update .Yes I know you can update for new one .But this is not my question .!

My English is readable .What to doing to keep my old Firefox 88 working extension add-ons . Usually I ask about Ublock not working .And advert flood me on website.

jscher2000 where is locate this certificates in firefox .?

Hi olek, this was the Reddit post I saw, but I have not tested it, so you may want to discuss with the posters there: https://www.reddit.com/r/firefox/comments/1jbhi1v/comment/mhv0lst/

78.10.0 Firefox ESR --> about:config --> xpinstall.signatures.required to false

uBlock Origin could not be verified for use in Firefox. Proceed with caution. works !!!

jscher2000 Why

1.I like green Padlock in ssl . 2.add folder favorite page in this old version is all fill dark color. New Firefox do not have it. 3.On the top new bar and menu bar is split about 3 millimeter I do not like that .

Mozilla Team focus about button left button right .button up button down .This is totally waste time .And very annoy .Mozilla team should focus about security ,All this movement with buttons is just waste time .

Thanks you for help .

78.10.0 Firefox ESR

So you downgraded even more so. Btw the 78.15.0esr (released October 5, 2021) was the last update for the old Firefox 78 ESR and not 78.10.0esr (released April 19, 2021). The old Firefox 78 ESR is based on the Firefox 78 Release (released back June 30, 2020) but with allowed security/stability fixes since.

Note your system you can use the current Firefox 115 ESR which is 115.21.0esr and it will be updated til 115.27.0esr in August unless Mozilla extends updates again.