diff --git a/nixbld-etc-nixos/configuration.nix b/nixbld-etc-nixos/configuration.nix
index a641cf6..ec9008c 100644
--- a/nixbld-etc-nixos/configuration.nix
+++ b/nixbld-etc-nixos/configuration.nix
@@ -10,10 +10,6 @@ let
   netifWifi = "wlp1s0";
   netifSit = "henet0";
   hydraWwwOutputs = "/var/www/hydra-outputs";
-  nur-no-pkgs = import (builtins.fetchTarball {
-    url = "https://github.com/nix-community/NUR/archive/bb3e415984e818099cd72776dc18dbbbb61cd364.tar.gz";
-    sha256 = "10mlxc4hj7nn3i766mjgjn9f1523w2v8msq895p7qp2j2wbx7b3g";
-  }) {};
 in
 {
   imports =
@@ -22,10 +18,9 @@ in
       ./backup-module.nix
       ./flarum.nix
       (builtins.fetchTarball {
-        url = "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/archive/v2.3.0/nixos-mailserver-v2.3.0.tar.gz";
-        sha256 = "0lpz08qviccvpfws2nm83n7m2r8add2wvfg9bljx9yxx8107r919";
+        url = "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/archive/nixos-20.09/nixos-mailserver-nixos-20.09.tar.gz";
+        sha256 = "1cfzlfdfiw8347cgi0y4akj528lpwplhdpq3fv5rw7fb1zq2w6ib";
       })
-      nur-no-pkgs.repos.mmilata.modules.jitsi-meet
     ];
 
   # Use the systemd-boot EFI boot loader.
@@ -372,23 +367,26 @@ in
     cookieSecure = true;
     disableRegistration = true;
     mailerPasswordFile = "/etc/nixos/secret/mailerpassword";
-    extraConfig =
-    ''
-    [indexer]
-    REPO_INDEXER_ENABLED = true
+    settings = {
+      indexer = {
+        REPO_INDEXER_ENABLED = true;
+      };
 
-    [mailer]
-    ENABLED = true
-    HOST = ssl.serverraum.org:587
-    FROM = sysop@m-labs.hk
-    USER = sysop@m-labs.hk
+      mailer = {
+        ENABLED = true;
+        HOST = "ssl.serverraum.org:587";
+        FROM = "sysop@m-labs.hk";
+        USER = "sysop@m-labs.hk";
+      };
 
-    [service]
-    ENABLE_NOTIFY_MAIL = true
+      service = {
+        ENABLE_NOTIFY_MAIL = true;
+      };
 
-    [attachment]
-    ALLOWED_TYPES = */*
-    '';
+      attachment = {
+        ALLOWED_TYPES = "*/*";
+      };
+    };
   };
   systemd.tmpfiles.rules = [
     "L+ '${config.services.gitea.stateDir}/custom/templates/home.tmpl' - - - - ${./gitea-home.tmpl}"
@@ -429,26 +427,24 @@ in
   security.acme.email = "sb" + "@m-labs.hk";
   security.acme.certs = {
     "nixbld.m-labs.hk" = {
-      group = "nginx";
-      user = "nginx";
       webroot = "/var/lib/acme/acme-challenge";
-      extraDomains = {
-        "m-labs.hk" = null;
-        "www.m-labs.hk" = null;
-        "conda.m-labs.hk" = null;
-        "lab.m-labs.hk" = null;
-        "git.m-labs.hk" = null;
-        "chat.m-labs.hk" = null;
-        "hooks.m-labs.hk" = null;
-        "forum.m-labs.hk" = null;
-        "perso.m-labs.hk" = null;
-        "call.m-labs.hk" = null;
-        "nmigen.org" = null;
-        "www.nmigen.org" = null;
+      extraDomainNames = [
+        "m-labs.hk"
+        "www.m-labs.hk"
+        "conda.m-labs.hk"
+        "lab.m-labs.hk"
+        "git.m-labs.hk"
+        "chat.m-labs.hk"
+        "hooks.m-labs.hk"
+        "forum.m-labs.hk"
+        "perso.m-labs.hk"
+        "call.m-labs.hk"
+        "nmigen.org"
+        "www.nmigen.org"
 
-        "openhardware.hk" = null;
-        "git.openhardware.hk" = null;
-      };
+        "openhardware.hk"
+        "git.openhardware.hk"
+      ];
     };
   };
   services.nginx = {
@@ -601,6 +597,7 @@ in
       };
       "call.m-labs.hk" = {
         useACMEHost = "nixbld.m-labs.hk";
+        enableACME = false;
         forceSSL = true;
       };
       "perso.m-labs.hk" = {
@@ -679,9 +676,7 @@ in
     loginAccounts = (import /etc/nixos/secret/email_accounts.nix);
     certificateScheme = 3;
   };
-  security.acme.certs."${config.mailserver.fqdn}".extraDomains = {
-    "mail.nmigen.org" = null;
-  };
+  security.acme.certs."${config.mailserver.fqdn}".extraDomainNames = [ "mail.nmigen.org" ];
 
   containers.openhardwarehk = {
     autoStart = true;
@@ -695,11 +690,11 @@ in
           appName = "Open Hardware HK";
           cookieSecure = true;
           disableRegistration = true;
-          extraConfig =
-          ''
-          [attachment]
-          ALLOWED_TYPES = */*
-          '';
+          settings = {
+            attachment = {
+              ALLOWED_TYPES = "*/*";
+            };
+          };
         };
       };
   };