I haven't seen an official announcement or new end-of-support date yet, but according to the 08-Jul-2024 Neowin article Mozilla wants you to like Firefox over Chrome, Edge with extended Windows 7/8/8.1 support Mozilla has decided to extend support for Win 7 / 8.x beyond September 2024. Martin Brinkmann stated "Mozilla plans to extend support for Firefox on Windows 7 and 8/8.1 (which uses Firefox 115 ESR)" in their 09-Jul-2024 ghacks.net article at Firefox 128: big feature release and new ESR-base but provided no further details.
Kudos to Cybertooth for posting about this today <here> in the AskWoody forum.
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Dell Inspiron 15 5584 * 64-bit Win 10 Pro v22H2 build 19045.4529 * Firefox v127.0.2 * Microsoft Defender v4.18.24050.7-1.1.24060.5 * Malwarebytes Premium v5.1.6.117-1.0.1270 * Macrium Reflect Free v8.0.7783