Even with Firefox 48, not every user will get e10s: Dotzler said that a big chunk of the user base would not see e10s in August. "The groups that will have to wait a bit for E10S account for about half of our release users and include Windows XP users, users with screen readers, RTL [right-to-left language writing] users [such as Arabic and Hebrew], and the largest group, extension users," Dotzler wrote.
The last group will be impacted by e10s because Firefox's aged add-on model assumed that the browser and content used the same memory space; existing add-ons must be modified. Mozilla has published a list of e10s-compatible add-ons that showed 12 of the top 20 Firefox extensions now work. Notable exceptions included NoScript Security Suite and Ghostery.
Last year, Mozilla announced it would overhaul Firefox's add-on technology to make it compatible with Chrome', so that developers can easily make their extensions Firefox-ready. (Microsoft has taken a similar approach with Edge.) When that happens, the multi-process design will not affect extensions.
At some point, Mozilla intends to isolate add-ons in their own processes.
"E10S is the largest change we've ever made to Firefox and we hope you'll help us get through this with as few surprises as possible," said Dotzler. "To help out, get on Beta and let us know what you find."
When available, the beta of Firefox 48 can be downloaded for Windows, OS X and Linux from Mozilla's website.
It's unclear whether, Dotzler's assertions notwithstanding, e10s and modern process management will rescue Firefox from the significant decline it's suffered in the last several years. According to analytics vendor Net Applications, Firefox's global user share, an estimate of the percentage of all users running Mozilla's browser, fell to 8.9% in May, the lowest level in 11 years.
In the last two years, Firefox's user share has plummeted by 47%, and from its peak in 2010, by 65%. Most of those losses have been assimilated by Chrome, which is now the world's top browser.
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