OptiFine seemingly does not clean up its features list anytime a new update has appeared with the removal of an option or introduction of an option. I did my best to find outdated features or options, though there may be a lot more that are fundamentally useless behind the scenes.
Ingame
1.8
Details Menu
Alternate Blocks: Just reloads resources, this button already exists in the main Video Settings screen.
Dropped Items: The code for the 2D items was removed in 1.8, OptiFine does not add it back.
Translucent Blocks: This seemingly does nothing, can't identify a difference between fast & fancy.
1.9+ to 1.16+
Details Menu
Dropped Items: The code for the 2D items was removed in 1.8, OptiFine does not add it back.
Translucent Blocks: This seemingly does nothing, can't identify a difference between fast & fancy.
Website
Features
"Performance: VSync": Minecraft has allowed you to use VSync for a very long time, this is no longer an OptiFine only feature.
"Smart Advanced OpenGL": This was removed in 1.8 and above, there is no mention of this anywhere ingame.
"Mipmaps": Minecraft has allowed you to change the Mipmaps level, so mention of this can be removed, but OptiFine has control over the mipmap type. This can be expanded from just "Nearest, Linear" to "Nearest, Linear, Bilinear, Trilinear".
"Natural Textures": This is just the Alternate Blocks effect, but renamed.
"Configurable Details": This mentions "- Show Capes - ON, OFF (supports HD capes)", while HD capes are only available to a select few people, so the probability of HD capes should not be mentioned to resolve confusion from users.
"Configurable animations": The water & lava mentions Dynamic, however this has not been an option since I believe 1.8. It also seems that this section has not seen an update to the list since pre-1.4.7, seeing as fireworks are not mentioned.
"Fast Texturepack Switching": This was introduced to Vanilla in 1.6.
"Fullscreen Resolution": This was introduced in 1.14.
"Debug": These are already disabled by default, and are only activated through SHIFT+F3 & ALT+F3.
Description of Issue
OptiFine seemingly does not clean up its features list anytime a new update has appeared with the removal of an option or introduction of an option. I did my best to find outdated features or options, though there may be a lot more that are fundamentally useless behind the scenes.
Ingame
1.8
Details Menu
1.9+ to 1.16+
Details Menu
Website