Hi,
When i use the ligatures codes starting by ss the ligatures are not considered.
Only the stylistics sets like zero or onum working. The other way around for some others (like the Fira code repo owner (third referral)
And when we push another value than true to editor.fontLigatures in settings no one ligatures work.
Refs :
(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:
Same on Linux, so it seems OS independent.
Tried without the single quotes:
"editor.fontFamily": "'Fira Code'",
"editor.fontLigatures": "ss01, ss02",
..which made no difference, it keeps the >= symbol with the diagonal line instead of the flat line:

OS: Ubuntu 18.04
VScode 1.40.1
fonts-firacode version: 1.204-2 installed from ubuntu universe repository
I'm seeing this issue with the following version combinations:
VS Code v1.40.0 and v1.40.1
Fira Code v2.0
OS Windows 10, 64-bit
@wboka It's not a version combination problem i think, because the font added ligatures characters in the v2.0 and VS Code implemented this editable setting at 1.40.0 (Refer to second link in first post)
See https://github.com/microsoft/vscode/issues/84018
and using Fira Code v2 (v1 doesn't support stylistic sets)!
Try adding calt to your list.
"editor.fontLigatures": "'zero', 'ss02', 'ss03', 'ss04', 'ss05', 'calt'",
[You might also try adding liga as well to the list, although I didn't have to.]
Bit of a hidden gotcha IMO. This works for me, it didn't without the calt:
"editor.fontFamily": "Fira Code",
"editor.fontLigatures":"'zero', 'ss02', 'ss03', 'ss04', 'ss05', 'calt'",

And definitely try a reload between changes.
@ArturoDent Doesn't seem to change anything.
"editor.fontLigatures": "'ss01', 'ss02', 'ss03', 'ss04', 'ss05', 'ss06', 'ss19', 'ss20', 'calt'"
The only visible changement is when i add calt to the array, the ligatures are okay but not the horizontal bar of ss02 ligature

Just in case: I did first delete the Fira Code v1 fonts before installing v2. I would suggest doing that again.
@pierredarrieutort Have you uninstalled the previous Fira Code? Restarted, and then installed the new Fira Code?
I feel bad now, it was a problem to update the font, a fresh install resolved my problems.
I had some old versions (v1.206 & v2.0) of the font installed along side each other. 馃う鈥嶁檪
Thanks for the help everyone! 馃帀
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I feel bad now, it was a problem to update the font, a fresh install resolved my problems.