diff --git a/classes/handler/public.php b/classes/handler/public.php
index b11c8ba04..ea2a0c5ef 100755
--- a/classes/handler/public.php
+++ b/classes/handler/public.php
@@ -950,7 +950,7 @@ class Handler_Public extends Handler {
 								WHERE id = ?");
 							$sth->execute([$id]);
 
-							Pref_Users::resetUserPassword($id, true);
+							Pref_Users::_reset_password($id, true);
 
 							print "<p>"."Completed."."</p>";
 
diff --git a/classes/pref/filters.php b/classes/pref/filters.php
index 62bcb8f59..95f0fcfc0 100755
--- a/classes/pref/filters.php
+++ b/classes/pref/filters.php
@@ -162,7 +162,7 @@ class Pref_Filters extends Handler_Protected {
 		print json_encode($rv);
 	}
 
-	private function getfilterrules_list($filter_id) {
+	private function _get_rules_list($filter_id) {
 		$sth = $this->pdo->prepare("SELECT reg_exp,
 			inverse,
 			match_on,
@@ -250,7 +250,7 @@ class Pref_Filters extends Handler_Protected {
 
 		while ($line = $sth->fetch()) {
 
-			$name = $this->getFilterName($line["id"]);
+			$name = $this->_get_name($line["id"]);
 
 			$match_ok = false;
 			if ($filter_search) {
@@ -292,7 +292,7 @@ class Pref_Filters extends Handler_Protected {
 			$filter['checkbox'] = false;
 			$filter['last_triggered'] = $line["last_triggered"] ? TimeHelper::make_local_datetime($line["last_triggered"], false) : null;
 			$filter['enabled'] = sql_bool_to_bool($line["enabled"]);
-			$filter['rules'] = $this->getfilterrules_list($line['id']);
+			$filter['rules'] = $this->_get_rules_list($line['id']);
 
 			if (!$filter_search || $match_ok) {
 				array_push($folder['items'], $filter);
@@ -391,7 +391,7 @@ class Pref_Filters extends Handler_Protected {
 					$data = htmlspecialchars((string)json_encode($line));
 
 					print "<li><input dojoType='dijit.form.CheckBox' type='checkbox' onclick='Lists.onRowChecked(this)'>
-						<span onclick='App.dialogOf(this).editRule(this)'>".$this->getRuleName($line)."</span>".
+						<span onclick='App.dialogOf(this).editRule(this)'>".$this->_get_rule_name($line)."</span>".
 						format_hidden("rule[]", $data)."</li>";
 				}
 			}
@@ -433,7 +433,7 @@ class Pref_Filters extends Handler_Protected {
 					$data = htmlspecialchars((string)json_encode($line));
 
 					print "<li><input dojoType='dijit.form.CheckBox' type='checkbox' onclick='Lists.onRowChecked(this)'>
-						<span onclick='App.dialogOf(this).editAction(this)'>".$this->getActionName($line)."</span>".
+						<span onclick='App.dialogOf(this).editAction(this)'>".$this->_get_action_name($line)."</span>".
 						format_hidden("action[]", $data)."</li>";
 				}
 			}
@@ -482,7 +482,7 @@ class Pref_Filters extends Handler_Protected {
 		}
 	}
 
-	private function getRuleName($rule) {
+	private function _get_rule_name($rule) {
 		if (!$rule) $rule = json_decode(clean($_REQUEST["rule"]), true);
 
 		$feeds = $rule["feed_id"];
@@ -523,10 +523,10 @@ class Pref_Filters extends Handler_Protected {
 	}
 
 	function printRuleName() {
-		print $this->getRuleName(json_decode(clean($_REQUEST["rule"]), true));
+		print $this->_get_rule_name(json_decode(clean($_REQUEST["rule"]), true));
 	}
 
-	private function getActionName($action) {
+	private function _get_action_name($action) {
 		$sth = $this->pdo->prepare("SELECT description FROM
 			ttrss_filter_actions WHERE id = ?");
 		$sth->execute([(int)$action["action_id"]]);
@@ -561,7 +561,7 @@ class Pref_Filters extends Handler_Protected {
 	}
 
 	function printActionName() {
-		print $this->getActionName(json_decode(clean($_REQUEST["action"]), true));
+		print $this->_get_action_name(json_decode(clean($_REQUEST["action"]), true));
 	}
 
 	function editSave() {
@@ -581,7 +581,7 @@ class Pref_Filters extends Handler_Protected {
 
 		$sth->execute([$enabled, $match_any_rule, $inverse, $title, $filter_id, $_SESSION['uid']]);
 
-		$this->saveRulesAndActions($filter_id);
+		$this->_save_rules_and_actions($filter_id);
 
 		$this->pdo->commit();
 	}
@@ -596,7 +596,7 @@ class Pref_Filters extends Handler_Protected {
 		$sth->execute(array_merge($ids, [$_SESSION['uid']]));
 	}
 
-	private function saveRulesAndActions($filter_id)
+	private function _save_rules_and_actions($filter_id)
 	{
 
 		$sth = $this->pdo->prepare("DELETE FROM ttrss_filters2_rules WHERE filter_id = ?");
@@ -696,7 +696,7 @@ class Pref_Filters extends Handler_Protected {
 
 		if ($row = $sth->fetch()) {
 			$filter_id = $row['id'];
-			$this->saveRulesAndActions($filter_id);
+			$this->_save_rules_and_actions($filter_id);
 		}
 
 		$this->pdo->commit();
@@ -941,7 +941,7 @@ class Pref_Filters extends Handler_Protected {
 		print "</form>";
 	}
 
-	private function getFilterName($id) {
+	private function _get_name($id) {
 
 		$sth = $this->pdo->prepare(
 			"SELECT title,match_any_rule,f.inverse AS inverse,COUNT(DISTINCT r.id) AS num_rules,COUNT(DISTINCT a.id) AS num_actions
@@ -970,7 +970,7 @@ class Pref_Filters extends Handler_Protected {
 			$actions = "";
 
 			if ($line = $sth->fetch()) {
-				$actions = $this->getActionName($line);
+				$actions = $this->_get_action_name($line);
 
 				$num_actions -= 1;
 			}
@@ -1012,12 +1012,12 @@ class Pref_Filters extends Handler_Protected {
 
 			$this->pdo->commit();
 
-			$this->optimizeFilter($base_id);
+			$this->_optimize($base_id);
 
 		}
 	}
 
-	private function optimizeFilter($id) {
+	private function _optimize($id) {
 
 		$this->pdo->beginTransaction();
 
diff --git a/classes/pref/prefs.php b/classes/pref/prefs.php
index 6e4deb223..81b7767eb 100644
--- a/classes/pref/prefs.php
+++ b/classes/pref/prefs.php
@@ -268,7 +268,7 @@ class Pref_Prefs extends Handler_Protected {
 				AND owner_uid = :uid");
 		$sth->execute([":profile" => $_SESSION['profile'], ":uid" => $_SESSION['uid']]);
 
-		$this->initialize_user_prefs($_SESSION["uid"], $_SESSION["profile"]);
+		$this->_init_user_prefs($_SESSION["uid"], $_SESSION["profile"]);
 
 		echo __("Your preferences are now set to default values.");
 	}
@@ -588,9 +588,9 @@ class Pref_Prefs extends Handler_Protected {
 
 		if ($profile) {
 			print_notice(__("Some preferences are only available in default profile."));
-			$this->initialize_user_prefs($_SESSION["uid"], $profile);
+			$this->_init_user_prefs($_SESSION["uid"], $profile);
 		} else {
-			$this->initialize_user_prefs($_SESSION["uid"]);
+			$this->_init_user_prefs($_SESSION["uid"]);
 		}
 
 		$prefs_available = [];
@@ -621,7 +621,7 @@ class Pref_Prefs extends Handler_Protected {
 			}
 
 			$pref_name = $line["pref_name"];
-			$short_desc = $this->getShortDesc($pref_name);
+			$short_desc = $this->_get_short_desc($pref_name);
 
 			if (!$short_desc)
 				continue;
@@ -629,7 +629,7 @@ class Pref_Prefs extends Handler_Protected {
 			$prefs_available[$pref_name] = [
 				'type_name' => $line["type_name"],
 				'value' => $line['value'],
-				'help_text' => $this->getHelpText($pref_name),
+				'help_text' => $this->_get_help_text($pref_name),
 				'short_desc' => $short_desc
 			];
 		}
@@ -1318,14 +1318,14 @@ class Pref_Prefs extends Handler_Protected {
 
 	}
 
-	private function getShortDesc($pref_name) {
+	private function _get_short_desc($pref_name) {
 		if (isset($this->pref_help[$pref_name][0])) {
 			return $this->pref_help[$pref_name][0];
 		}
 		return "";
 	}
 
-	private function getHelpText($pref_name) {
+	private function _get_help_text($pref_name) {
 		if (isset($this->pref_help[$pref_name][1])) {
 			return $this->pref_help[$pref_name][1];
 		}
@@ -1380,7 +1380,7 @@ class Pref_Prefs extends Handler_Protected {
 		<?php
 	}
 
-	private function encryptAppPassword($password) {
+	private function _encrypt_app_password($password) {
 		$salt = substr(bin2hex(get_random_bytes(24)), 0, 24);
 
 		return "SSHA-512:".hash('sha512', $salt . $password). ":$salt";
@@ -1399,7 +1399,7 @@ class Pref_Prefs extends Handler_Protected {
 	function generateAppPassword() {
 		$title = clean($_REQUEST['title']);
 		$new_password = make_password(16);
-		$new_password_hash = $this->encryptAppPassword($new_password);
+		$new_password_hash = $this->_encrypt_app_password($new_password);
 
 		print_warning(T_sprintf("Generated password <strong>%s</strong> for %s. Please remember it for future reference.", $new_password, $title));
 
@@ -1413,7 +1413,7 @@ class Pref_Prefs extends Handler_Protected {
 		$this->appPasswordList();
 	}
 
-	static function initialize_user_prefs($uid, $profile = false) {
+	static function _init_user_prefs($uid, $profile = false) {
 
 		if (get_schema_version() < 63) $profile_qpart = "";
 
diff --git a/classes/pref/system.php b/classes/pref/system.php
index 2a97ec6f0..f0a5f7b7f 100644
--- a/classes/pref/system.php
+++ b/classes/pref/system.php
@@ -23,7 +23,7 @@ class Pref_System extends Handler_Administrative {
 		print preg_replace( '%^.*<body>(.*)</body>.*$%ms','$1', (string)$info);
 	}
 
-	private function log_viewer(int $page, int $severity) {
+	private function _log_viewer(int $page, int $severity) {
 		$errno_values = [];
 
 		switch ($severity) {
@@ -154,7 +154,7 @@ class Pref_System extends Handler_Administrative {
 			<div dojoType='dijit.layout.AccordionPane' style='padding : 0' title='<i class="material-icons">report</i> <?= __('Event Log') ?>'>
 				<?php
 					if (LOG_DESTINATION == "sql") {
-						$this->log_viewer($page, $severity);
+						$this->_log_viewer($page, $severity);
 					} else {
 						print_notice("Please set LOG_DESTINATION to 'sql' in config.php to enable database logging.");
 					}
diff --git a/classes/pref/users.php b/classes/pref/users.php
index bc125d0ce..d2dd06fd8 100644
--- a/classes/pref/users.php
+++ b/classes/pref/users.php
@@ -166,7 +166,7 @@ class Pref_Users extends Handler_Administrative {
 			}
 		}
 
-		static function resetUserPassword($uid, $format_output = false) {
+		static function _reset_password($uid, $format_output = false) {
 
 			$pdo = Db::pdo();
 
@@ -199,7 +199,7 @@ class Pref_Users extends Handler_Administrative {
 
 		function resetPass() {
 			$uid = clean($_REQUEST["id"]);
-			self::resetUserPassword($uid);
+			self::_reset_password($uid);
 		}
 
 		function index() {
@@ -220,7 +220,7 @@ class Pref_Users extends Handler_Administrative {
 				$sort = "login";
 			}
 
-			$sort = $this->validate_field($sort,
+			$sort = $this->_validate_field($sort,
 				["login", "access_level", "created", "num_feeds", "created", "last_login"], "login");
 
 			if ($sort != "login") $sort = "$sort DESC";
@@ -314,7 +314,7 @@ class Pref_Users extends Handler_Administrative {
 		<?php
 	}
 
-	function validate_field($string, $allowed, $default = "") {
+	private function _validate_field($string, $allowed, $default = "") {
 			if (in_array($string, $allowed))
 				return $string;
 			else
diff --git a/classes/rpc.php b/classes/rpc.php
index b91684bcd..1bfea621b 100755
--- a/classes/rpc.php
+++ b/classes/rpc.php
@@ -52,7 +52,7 @@ class RPC extends Handler_Protected {
 					$profile_id = $row['id'];
 
 					if ($profile_id) {
-						Pref_Prefs::initialize_user_prefs($_SESSION["uid"], $profile_id);
+						Pref_Prefs::_init_user_prefs($_SESSION["uid"], $profile_id);
 					}
 				}
 			}
diff --git a/classes/userhelper.php b/classes/userhelper.php
index 8eb97f5d0..744f77a23 100644
--- a/classes/userhelper.php
+++ b/classes/userhelper.php
@@ -41,7 +41,7 @@ class UserHelper {
 				$_SESSION["user_agent"] = sha1($_SERVER['HTTP_USER_AGENT']);
 				$_SESSION["pwd_hash"] = $row["pwd_hash"];
 
-				Pref_Prefs::initialize_user_prefs($_SESSION["uid"]);
+				Pref_Prefs::_init_user_prefs($_SESSION["uid"]);
 
 				return true;
 			}
@@ -64,7 +64,7 @@ class UserHelper {
 
 			$_SESSION["ip_address"] = UserHelper::get_user_ip();
 
-			Pref_Prefs::initialize_user_prefs($_SESSION["uid"]);
+			Pref_Prefs::_init_user_prefs($_SESSION["uid"]);
 
 			return true;
 		}