diff --git a/nixos/modules/services/networking/i2pd.nix b/nixos/modules/services/networking/i2pd.nix
index 578376764eb..abb7a4e9137 100644
--- a/nixos/modules/services/networking/i2pd.nix
+++ b/nixos/modules/services/networking/i2pd.nix
@@ -147,7 +147,7 @@ let
   host = ${tun.address}
   port = ${tun.port}
   inport = ${tun.inPort}
-  accesslist = ${concatStringSep "," tun.accessList}
+  accesslist = ${builtins.concatStringsSep "," tun.accessList}
   '')
   }
   '';