diff --git a/nixos/doc/manual/from_md/release-notes/rl-2111.section.xml b/nixos/doc/manual/from_md/release-notes/rl-2111.section.xml
index de2cd7bef6d6..0cd293df40cd 100644
--- a/nixos/doc/manual/from_md/release-notes/rl-2111.section.xml
+++ b/nixos/doc/manual/from_md/release-notes/rl-2111.section.xml
@@ -570,6 +570,17 @@
           6.0.0 to 9.0.0
         </para>
       </listitem>
+      <listitem>
+        <para>
+          <literal>tt-rss</literal> was upgraded to the commit on
+          2021-06-21, which has breaking changes. If you use
+          <literal>services.tt-rss.extraConfig</literal> you should
+          migrate to the <literal>putenv</literal>-style configuration.
+          See
+          <link xlink:href="https://community.tt-rss.org/t/rip-config-php-hello-classes-config-php/4337">this
+          Discourse post</link> in the tt-rss forums for more details.
+        </para>
+      </listitem>
       <listitem>
         <para>
           The following Visual Studio Code extensions were renamed to
diff --git a/nixos/doc/manual/release-notes/rl-2111.section.md b/nixos/doc/manual/release-notes/rl-2111.section.md
index 1ce78a4d7745..3eefe138fb0d 100644
--- a/nixos/doc/manual/release-notes/rl-2111.section.md
+++ b/nixos/doc/manual/release-notes/rl-2111.section.md
@@ -146,6 +146,8 @@ pt-services.clipcat.enable).
 
 - the `mingw-64` package has been upgraded from 6.0.0 to 9.0.0
 
+- `tt-rss` was upgraded to the commit on 2021-06-21, which has breaking changes. If you use `services.tt-rss.extraConfig` you should migrate to the `putenv`-style configuration. See [this Discourse post](https://community.tt-rss.org/t/rip-config-php-hello-classes-config-php/4337) in the tt-rss forums for more details.
+
 - The following Visual Studio Code extensions were renamed to keep the naming convention uniform.
   - `bbenoist.Nix` -> `bbenoist.nix`
   - `CoenraadS.bracket-pair-colorizer` -> `coenraads.bracket-pair-colorizer`
diff --git a/nixos/modules/services/web-apps/tt-rss.nix b/nixos/modules/services/web-apps/tt-rss.nix
index b78487cc9281..ed13845915c4 100644
--- a/nixos/modules/services/web-apps/tt-rss.nix
+++ b/nixos/modules/services/web-apps/tt-rss.nix
@@ -19,82 +19,84 @@ let
   mysqlLocal = cfg.database.createLocally && cfg.database.type == "mysql";
   pgsqlLocal = cfg.database.createLocally && cfg.database.type == "pgsql";
 
-  tt-rss-config = pkgs.writeText "config.php" ''
+  tt-rss-config = let
+    password =
+      if (cfg.database.password != null) then
+        "${(escape ["'" "\\"] cfg.database.password)}"
+      else if (cfg.database.passwordFile != null) then
+        "file_get_contents('${cfg.database.passwordFile}'"
+      else
+        ""
+      ;
+  in pkgs.writeText "config.php" ''
     <?php
+      putenv('TTRSS_PHP_EXECUTABLE=${pkgs.php}/bin/php');
 
-      define('PHP_EXECUTABLE', '${pkgs.php}/bin/php');
+      putenv('TTRSS_LOCK_DIRECTORY=${lockDir}');
+      putenv('TTRSS_CACHE_DIR=${cacheDir}');
+      putenv('TTRSS_ICONS_DIR=${feedIconsDir}');
+      putenv('TTRSS_ICONS_URL=${feedIconsDir}');
+      putenv('TTRSS_SELF_URL_PATH=${cfg.selfUrlPath}');
 
-      define('LOCK_DIRECTORY', '${lockDir}');
-      define('CACHE_DIR', '${cacheDir}');
-      define('ICONS_DIR', '${feedIconsDir}');
-      define('ICONS_URL', '${feedIconsDir}');
-      define('SELF_URL_PATH', '${cfg.selfUrlPath}');
+      putenv('TTRSS_MYSQL_CHARSET=UTF8');
 
-      define('MYSQL_CHARSET', 'UTF8');
+      putenv('TTRSS_DB_TYPE=${cfg.database.type}');
+      putenv('TTRSS_DB_HOST=${optionalString (cfg.database.host != null) cfg.database.host}');
+      putenv('TTRSS_DB_USER=${cfg.database.user}');
+      putenv('TTRSS_DB_NAME=${cfg.database.name}');
+      putenv('TTRSS_DB_PASS=${password}');
+      putenv('TTRSS_DB_PORT=${toString dbPort}');
 
-      define('DB_TYPE', '${cfg.database.type}');
-      define('DB_HOST', '${optionalString (cfg.database.host != null) cfg.database.host}');
-      define('DB_USER', '${cfg.database.user}');
-      define('DB_NAME', '${cfg.database.name}');
-      define('DB_PASS', ${
-        if (cfg.database.password != null) then
-          "'${(escape ["'" "\\"] cfg.database.password)}'"
-        else if (cfg.database.passwordFile != null) then
-          "file_get_contents('${cfg.database.passwordFile}')"
-        else
-          "''"
-      });
-      define('DB_PORT', '${toString dbPort}');
+      putenv('TTRSS_AUTH_AUTO_CREATE=${boolToString cfg.auth.autoCreate}');
+      putenv('TTRSS_AUTH_AUTO_LOGIN=${boolToString cfg.auth.autoLogin}');
 
-      define('AUTH_AUTO_CREATE', ${boolToString cfg.auth.autoCreate});
-      define('AUTH_AUTO_LOGIN', ${boolToString cfg.auth.autoLogin});
-
-      define('FEED_CRYPT_KEY', '${escape ["'" "\\"] cfg.feedCryptKey}');
+      putenv('TTRSS_FEED_CRYPT_KEY=${escape ["'" "\\"] cfg.feedCryptKey}');
 
 
-      define('SINGLE_USER_MODE', ${boolToString cfg.singleUserMode});
+      putenv('TTRSS_SINGLE_USER_MODE=${boolToString cfg.singleUserMode}');
 
-      define('SIMPLE_UPDATE_MODE', ${boolToString cfg.simpleUpdateMode});
+      putenv('TTRSS_SIMPLE_UPDATE_MODE=${boolToString cfg.simpleUpdateMode}');
 
-      // Never check for updates - the running version of the code should be
-      // controlled entirely by the version of TT-RSS active in the current Nix
-      // profile. If TT-RSS updates itself to a version requiring a database
-      // schema upgrade, and then the SystemD tt-rss.service is restarted, the
-      // old code copied from the Nix store will overwrite the updated version,
-      // causing the code to detect the need for a schema "upgrade" (since the
-      // schema version in the database is different than in the code), but the
-      // update schema operation in TT-RSS will do nothing because the schema
-      // version in the database is newer than that in the code.
-      define('CHECK_FOR_UPDATES', false);
+      # Never check for updates - the running version of the code should
+      # be controlled entirely by the version of TT-RSS active in the
+      # current Nix profile. If TT-RSS updates itself to a version
+      # requiring a database schema upgrade, and then the SystemD
+      # tt-rss.service is restarted, the old code copied from the Nix
+      # store will overwrite the updated version, causing the code to
+      # detect the need for a schema "upgrade" (since the schema version
+      # in the database is different than in the code), but the update
+      # schema operation in TT-RSS will do nothing because the schema
+      # version in the database is newer than that in the code.
+      putenv('TTRSS_CHECK_FOR_UPDATES=false');
 
-      define('FORCE_ARTICLE_PURGE', ${toString cfg.forceArticlePurge});
-      define('SESSION_COOKIE_LIFETIME', ${toString cfg.sessionCookieLifetime});
-      define('ENABLE_GZIP_OUTPUT', ${boolToString cfg.enableGZipOutput});
+      putenv('TTRSS_FORCE_ARTICLE_PURGE=${toString cfg.forceArticlePurge}');
+      putenv('TTRSS_SESSION_COOKIE_LIFETIME=${toString cfg.sessionCookieLifetime}');
+      putenv('TTRSS_ENABLE_GZIP_OUTPUT=${boolToString cfg.enableGZipOutput}');
 
-      define('PLUGINS', '${builtins.concatStringsSep "," cfg.plugins}');
+      putenv('TTRSS_PLUGINS=${builtins.concatStringsSep "," cfg.plugins}');
 
-      define('LOG_DESTINATION', '${cfg.logDestination}');
-      define('CONFIG_VERSION', ${toString configVersion});
+      putenv('TTRSS_LOG_DESTINATION=${cfg.logDestination}');
+      putenv('TTRSS_CONFIG_VERSION=${toString configVersion}');
 
 
-      define('PUBSUBHUBBUB_ENABLED', ${boolToString cfg.pubSubHubbub.enable});
-      define('PUBSUBHUBBUB_HUB', '${cfg.pubSubHubbub.hub}');
+      putenv('TTRSS_PUBSUBHUBBUB_ENABLED=${boolToString cfg.pubSubHubbub.enable}');
+      putenv('TTRSS_PUBSUBHUBBUB_HUB=${cfg.pubSubHubbub.hub}');
 
-      define('SPHINX_SERVER', '${cfg.sphinx.server}');
-      define('SPHINX_INDEX', '${builtins.concatStringsSep "," cfg.sphinx.index}');
+      putenv('TTRSS_SPHINX_SERVER=${cfg.sphinx.server}');
+      putenv('TTRSS_SPHINX_INDEX=${builtins.concatStringsSep "," cfg.sphinx.index}');
 
-      define('ENABLE_REGISTRATION', ${boolToString cfg.registration.enable});
-      define('REG_NOTIFY_ADDRESS', '${cfg.registration.notifyAddress}');
-      define('REG_MAX_USERS', ${toString cfg.registration.maxUsers});
+      putenv('TTRSS_ENABLE_REGISTRATION=${boolToString cfg.registration.enable}');
+      putenv('TTRSS_REG_NOTIFY_ADDRESS=${cfg.registration.notifyAddress}');
+      putenv('TTRSS_REG_MAX_USERS=${toString cfg.registration.maxUsers}');
 
-      define('SMTP_SERVER', '${cfg.email.server}');
-      define('SMTP_LOGIN', '${cfg.email.login}');
-      define('SMTP_PASSWORD', '${escape ["'" "\\"] cfg.email.password}');
-      define('SMTP_SECURE', '${cfg.email.security}');
+      putenv('TTRSS_SMTP_SERVER=${cfg.email.server}');
+      putenv('TTRSS_SMTP_LOGIN=${cfg.email.login}');
+      putenv('TTRSS_SMTP_PASSWORD=${escape ["'" "\\"] cfg.email.password}');
+      putenv('TTRSS_SMTP_SECURE=${cfg.email.security}');
 
-      define('SMTP_FROM_NAME', '${escape ["'" "\\"] cfg.email.fromName}');
-      define('SMTP_FROM_ADDRESS', '${escape ["'" "\\"] cfg.email.fromAddress}');
-      define('DIGEST_SUBJECT', '${escape ["'" "\\"] cfg.email.digestSubject}');
+      putenv('TTRSS_SMTP_FROM_NAME=${escape ["'" "\\"] cfg.email.fromName}');
+      putenv('TTRSS_SMTP_FROM_ADDRESS=${escape ["'" "\\"] cfg.email.fromAddress}');
+      putenv('TTRSS_DIGEST_SUBJECT=${escape ["'" "\\"] cfg.email.digestSubject}');
 
       ${cfg.extraConfig}
   '';
@@ -564,9 +566,12 @@ let
       "Z '${cfg.root}' 0755 ${cfg.user} tt_rss - -"
     ];
 
-    systemd.services.tt-rss =
-      {
+    systemd.services = {
+      phpfpm-tt-rss = mkIf (cfg.pool == "${poolName}") {
+        restartTriggers = [ tt-rss-config pkgs.tt-rss ];
+      };
 
+      tt-rss = {
         description = "Tiny Tiny RSS feeds update daemon";
 
         preStart = let
@@ -604,6 +609,9 @@ let
           ''}
           ln -sf "${tt-rss-config}" "${cfg.root}/config.php"
           chmod -R 755 "${cfg.root}"
+          chmod -R ug+rwX "${cfg.root}/${lockDir}"
+          chmod -R ug+rwX "${cfg.root}/${cacheDir}"
+          chmod -R ug+rwX "${cfg.root}/${feedIconsDir}"
         ''
 
         + (optionalString (cfg.database.type == "pgsql") ''
@@ -640,6 +648,7 @@ let
         wantedBy = [ "multi-user.target" ];
         requires = optional mysqlLocal "mysql.service" ++ optional pgsqlLocal "postgresql.service";
         after = [ "network.target" ] ++ optional mysqlLocal "mysql.service" ++ optional pgsqlLocal "postgresql.service";
+      };
     };
 
     services.mysql = mkIf mysqlLocal {
diff --git a/pkgs/servers/tt-rss/default.nix b/pkgs/servers/tt-rss/default.nix
index e91fed5ee160..39615a238e35 100644
--- a/pkgs/servers/tt-rss/default.nix
+++ b/pkgs/servers/tt-rss/default.nix
@@ -2,17 +2,28 @@
 
 stdenv.mkDerivation rec {
   pname = "tt-rss";
-  version = "2021-01-29";
-  rev = "6d8f2221b82b6a31becbeed8baf5e05ad9e053fe";
+  year = "21";
+  month = "06";
+  day = "21";
+  version = "20${year}-${month}-${day}";
+  rev = "cd26dbe64c9b14418f0b2d826a38a35c6bf8a270";
 
   src = fetchurl {
     url = "https://git.tt-rss.org/fox/tt-rss/archive/${rev}.tar.gz";
-    sha256 = "124c62hck631xlq5aa1miz9rbg711ygk7z1yx92m5dfcy630l7x5";
+    sha256 = "1dpmzi7hknv5rk2g1iw13r8zcxcwrhkd5hhf292ml0dw3cwki0gm";
   };
 
   installPhase = ''
+    runHook preInstall
+
     mkdir $out
     cp -ra * $out/
+
+    # see the code of Config::get_version(). you can check that the version in
+    # the footer of the preferences pages is not UNKNOWN
+    echo "${year}.${month}" > $out/version_static.txt
+
+    runHook postInstall
   '';
 
   meta = with lib; {