diff --git a/pkgs/by-name/si/signal-desktop-bin/copy-noto-emoji.py b/pkgs/by-name/si/signal-desktop-bin/copy-noto-emoji.py
index 8acaebcb23d7..c873c0b0db4d 100644
--- a/pkgs/by-name/si/signal-desktop-bin/copy-noto-emoji.py
+++ b/pkgs/by-name/si/signal-desktop-bin/copy-noto-emoji.py
@@ -18,24 +18,6 @@ import sys
 from pathlib import Path
 
 
-def signal_name_to_emoji(signal_emoji_name: str) -> str:
-    r"""Return the emoji corresponding to a Signal emoji name.
-
-    Signal emoji names are concatenations of UTF‐16 code units,
-    represented in lowercase big‐endian hex padded to four digits.
-
-    >>> signal_name_to_emoji("d83dde36200dd83cdf2bfe0f")
-    '😶‍🌫️'
-    >>> b"\xd8\x3d\xde\x36\x20\x0d\xd8\x3c\xdf\x2b\xfe\x0f".decode("utf-16-be")
-    '😶‍🌫️'
-    """
-    hex_bytes = zip(signal_emoji_name[::2], signal_emoji_name[1::2])
-    emoji_utf_16_be = bytes(
-        int("".join(hex_pair), 16) for hex_pair in hex_bytes
-    )
-    return emoji_utf_16_be.decode("utf-16-be")
-
-
 def emoji_to_noto_name(emoji: str) -> str:
     r"""Return the Noto emoji name of an emoji.
 
@@ -68,16 +50,15 @@ def _main() -> None:
 
     for signal_emoji_names in jumbomoji_packs.values():
         for signal_emoji_name in signal_emoji_names:
-            emoji = signal_name_to_emoji(signal_emoji_name)
 
             try:
                 shutil.copy(
-                    noto_png_path / f"emoji_u{emoji_to_noto_name(emoji)}.png",
-                    out_path / emoji,
+                    noto_png_path / f"emoji_u{emoji_to_noto_name(signal_emoji_name)}.png",
+                    out_path / signal_emoji_name,
                 )
             except FileNotFoundError:
                 print(
-                    f"Missing Noto emoji: {emoji} {signal_emoji_name}",
+                    f"Missing Noto emoji: {signal_emoji_name}",
                     file=sys.stderr,
                 )
                 continue
diff --git a/pkgs/by-name/si/signal-desktop-bin/generic.nix b/pkgs/by-name/si/signal-desktop-bin/generic.nix
index 9b0fd4aec65c..e50aeb231456 100644
--- a/pkgs/by-name/si/signal-desktop-bin/generic.nix
+++ b/pkgs/by-name/si/signal-desktop-bin/generic.nix
@@ -92,12 +92,12 @@ let
   });
 
   noto-emoji-sheet-32 = fetchurl {
-    url = "https://raw.githubusercontent.com/iamcal/emoji-data/refs/tags/v15.1.2/sheet_google_32.png";
-    hash = "sha256-S03NCTbvB5yeQl62WpLNjNGhjNErtgaOB6tAj/X8vPc=";
+    url = "https://raw.githubusercontent.com/iamcal/emoji-data/refs/tags/v16.0.0/sheet_google_32.png";
+    hash = "sha256-tBfp9s1LvBBla7/V4TtumiVFtV5qTPcxLXW+H6qjSVI=";
   };
   noto-emoji-sheet-64 = fetchurl {
-    url = "https://raw.githubusercontent.com/iamcal/emoji-data/refs/tags/v15.1.2/sheet_google_64.png";
-    hash = "sha256-kZYStR5xAuausSpOD6wJZRJZ1K6nPpweE3aYSgWntS4=";
+    url = "https://raw.githubusercontent.com/iamcal/emoji-data/refs/tags/v16.0.0/sheet_google_64.png";
+    hash = "sha256-eVoMWY0WLJpKriPyGIxge4ybwZEst9hDgkWfjekaOuE=";
   };
 in
 stdenv.mkDerivation rec {
@@ -263,8 +263,7 @@ stdenv.mkDerivation rec {
 
     # Fix the desktop link
     substituteInPlace $out/share/applications/signal-desktop.desktop \
-      --replace-fail "/${bindir}/signal-desktop" ${meta.mainProgram} \
-      --replace-fail "StartupWMClass=Signal" "StartupWMClass=signal"
+      --replace-fail "/${bindir}/signal-desktop" ${meta.mainProgram}
 
     mv $out/share/applications/signal{-desktop,}.desktop