diff --git a/classes/background-processes/class-post-conversion-process.php b/classes/background-processes/class-post-conversion-process.php
index 35ac1b3..e7b362e 100644
--- a/classes/background-processes/class-post-conversion-process.php
+++ b/classes/background-processes/class-post-conversion-process.php
@@ -65,7 +65,7 @@ protected function task( $post ) {
 		if ( $transliterated_name !== $post_name ) {
 			update_post_meta( $post->ID, '_wp_old_slug', $post_name );
 			// phpcs:ignore WordPress.DB.DirectDatabaseQuery
-			$wpdb->update( $wpdb->posts, [ 'post_name' => urlencode( $transliterated_name ) ], [ 'ID' => $post->ID ] );
+			$wpdb->update( $wpdb->posts, [ 'post_name' => rawurlencode( $transliterated_name ) ], [ 'ID' => $post->ID ] );
 
 			$this->log( __( 'Post slug converted:', 'cyr2lat' ) . ' ' . $post_name . ' => ' . $transliterated_name );
 		}
diff --git a/classes/background-processes/class-term-conversion-process.php b/classes/background-processes/class-term-conversion-process.php
index d29f397..a0a1304 100644
--- a/classes/background-processes/class-term-conversion-process.php
+++ b/classes/background-processes/class-term-conversion-process.php
@@ -64,7 +64,7 @@ protected function task( $term ) {
 
 		if ( $transliterated_slug !== $slug ) {
 			// phpcs:ignore WordPress.DB.DirectDatabaseQuery
-			$wpdb->update( $wpdb->terms, [ 'slug' => urlencode( $transliterated_slug ) ], [ 'term_id' => $term->term_id ] );
+			$wpdb->update( $wpdb->terms, [ 'slug' => rawurlencode( $transliterated_slug ) ], [ 'term_id' => $term->term_id ] );
 
 			$this->log( __( 'Term slug converted:', 'cyr2lat' ) . ' ' . $slug . ' => ' . $transliterated_slug );
 		}
diff --git a/classes/class-conversion-tables.php b/classes/class-conversion-tables.php
index da699d3..b83065c 100644
--- a/classes/class-conversion-tables.php
+++ b/classes/class-conversion-tables.php
@@ -553,13 +553,13 @@ public static function get( $locale = '' ) {
 					'ת' => 'th',
 				];
 				for ( $code = 0x0590; $code <= 0x05CF; $code ++ ) {
-					$table[ mb_chr( $code ) ] = '';
+					$table[ Mbstring::mb_chr( $code ) ] = '';
 				}
 				for ( $code = 0x05F0; $code <= 0x05F5; $code ++ ) {
-					$table[ mb_chr( $code ) ] = '';
+					$table[ Mbstring::mb_chr( $code ) ] = '';
 				}
 				for ( $code = 0xFB1D; $code <= 0xFB4F; $code ++ ) {
-					$table[ mb_chr( $code ) ] = '';
+					$table[ Mbstring::mb_chr( $code ) ] = '';
 				}
 				break;
 			// phpcs:disable PSR2.ControlStructures.SwitchDeclaration.TerminatingComment
diff --git a/classes/class-main.php b/classes/class-main.php
index 934845a..e7d181a 100644
--- a/classes/class-main.php
+++ b/classes/class-main.php
@@ -125,16 +125,18 @@ public function init_hooks() {
 	 * @param int    $post_ID       Post ID.
 	 * @param string $post_status   The post status.
 	 * @param string $post_type     Post type.
-	 * @param int    $post_parent   Post parent ID
+	 * @param int    $post_parent   Post parent ID.
 	 * @param string $original_slug The original post slug.
 	 *
 	 * @return string
 	 */
 	public function wp_unique_post_slug_filter( $slug, $post_ID, $post_status, $post_type, $post_parent, $original_slug ) {
-		return urlencode( $this->transliterate( urldecode( $slug ) ) );
+		return $this->transliterate_encoded( $slug );
 	}
 
 	/**
+	 * Filter wp_unique_term_slug.
+	 *
 	 * @param string $slug          Unique term slug.
 	 * @param object $term          Term object.
 	 * @param string $original_slug Slug originally passed to the function for testing.
@@ -142,17 +144,19 @@ public function wp_unique_post_slug_filter( $slug, $post_ID, $post_status, $post
 	 * @return string
 	 */
 	public function wp_unique_term_slug_filter( $slug, $term, $original_slug ) {
-		return urlencode( $this->transliterate( urldecode( $slug ) ) );
+		return $this->transliterate_encoded( $slug );
 	}
 
 	/**
+	 * Filter pre_term_slug.
+	 *
 	 * @param mixed  $value    Value of the term field.
 	 * @param string $taxonomy Taxonomy slug.
 	 *
 	 * @return string
 	 */
 	public function pre_term_slug_filter( $value, $taxonomy ) {
-		return urlencode( $this->transliterate( urldecode( $value ) ) );
+		return $this->transliterate_encoded( $value );
 	}
 
 	/**
@@ -211,7 +215,7 @@ protected function split_chinese_string( $string, $table ) {
 			return $string;
 		}
 
-		$chars  = mb_str_split( $string );
+		$chars  = Mbstring::mb_str_split( $string );
 		$string = '';
 
 		foreach ( $chars as $char ) {
@@ -225,6 +229,17 @@ protected function split_chinese_string( $string, $table ) {
 		return $string;
 	}
 
+	/**
+	 * Transliterate encoded url.
+	 *
+	 * @param string $url Url.
+	 *
+	 * @return string
+	 */
+	private function transliterate_encoded( $url ) {
+		return rawurlencode( $this->transliterate( urldecode( $url ) ) );
+	}
+
 	/**
 	 * Get transliteration table.
 	 *
diff --git a/classes/class-settings.php b/classes/class-settings.php
index 2894252..077f4cc 100644
--- a/classes/class-settings.php
+++ b/classes/class-settings.php
@@ -790,7 +790,7 @@ protected function transpose_chinese_table( $table ) {
 
 		$transposed_table = [];
 		foreach ( $table as $key => $item ) {
-			$hieroglyphs = mb_str_split( $item );
+			$hieroglyphs = Mbstring::mb_str_split( $item );
 			foreach ( $hieroglyphs as $hieroglyph ) {
 				$transposed_table[ $hieroglyph ] = $key;
 			}