In my .htaccess I have this
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RewriteCond %{HTTP_ACCEPT} "image/webp" RewriteRule .* - [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+webp] RewriteCond %{HTTP_USER_AGENT} iPhone.*Version/(\d{2}).*Safari RewriteCond %1 >13 RewriteRule .* - [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+webp]
### marker WEBP end ###
However these rules should not enough to cover all mobile situations , am I right ?