diff --git a/includes/admin/post-types/meta-boxes/class-sp-meta-box-outcome-details.php b/includes/admin/post-types/meta-boxes/class-sp-meta-box-outcome-details.php
index 50ba94f9..2b44744b 100644
--- a/includes/admin/post-types/meta-boxes/class-sp-meta-box-outcome-details.php
+++ b/includes/admin/post-types/meta-boxes/class-sp-meta-box-outcome-details.php
@@ -45,7 +45,7 @@ class SP_Meta_Box_Outcome_Details extends SP_Meta_Box_Config {
 		</p>
 		<p><strong><?php _e( 'Abbreviation', 'sportspress' ); ?></strong></p>
 		<p>
-			<input name="sp_abbreviation" type="text" id="sp_abbreviation" value="<?php echo $abbreviation; ?>" placeholder="<?php echo mb_substr( $post->post_title, 0, 1 ); ?>">
+			<input name="sp_abbreviation" type="text" id="sp_abbreviation" value="<?php echo $abbreviation; ?>" placeholder="<?php echo sp_substr( $post->post_title, 0, 1 ); ?>">
 		</p>
 		<p><strong><?php _e( 'Color', 'sportspress' ); ?></strong></p>
 		<p>
diff --git a/includes/class-sp-player.php b/includes/class-sp-player.php
index 4ee098f3..d2959bad 100644
--- a/includes/class-sp-player.php
+++ b/includes/class-sp-player.php
@@ -528,7 +528,7 @@ class SP_Player extends SP_Custom_Post {
 			if ( $outcomes ):
 				$outcome = reset( $outcomes );
 				$abbreviation = sp_get_abbreviation( $outcome->ID );
-				if ( empty( $abbreviation ) ) $abbreviation = mb_strtoupper( mb_substr( $outcome->post_title, 0, 1 ) );
+				if ( empty( $abbreviation ) ) $abbreviation = sp_strtoupper( sp_substr( $outcome->post_title, 0, 1 ) );
 				$totals['streak'] = $abbreviation . $streak['count'];
 			endif;
 
diff --git a/includes/class-sp-team.php b/includes/class-sp-team.php
index f2146405..71299822 100644
--- a/includes/class-sp-team.php
+++ b/includes/class-sp-team.php
@@ -323,7 +323,7 @@ class SP_Team extends SP_Custom_Post {
 				$outcome = reset( $outcomes );
 				$abbreviation = get_post_meta( $outcome->ID, 'sp_abbreviation', true );
 				if ( ! $abbreviation )
-					$abbreviation = mb_substr( $outcome->post_title, 0, 1 );
+					$abbreviation = sp_substr( $outcome->post_title, 0, 1 );
 				$totals['streak'] = $abbreviation . $streak['count'];
 			endif;
 
diff --git a/includes/sp-api-functions.php b/includes/sp-api-functions.php
index 01f17c7c..c7f5f81b 100644
--- a/includes/sp-api-functions.php
+++ b/includes/sp-api-functions.php
@@ -296,7 +296,7 @@ function sp_team_abbreviation( $post = 0, $forced = false ) {
 	if ( $abbreviation ) {
 		return $abbreviation;
 	} else {
-		return $forced ? mb_substr( mb_strtoupper( sp_team_short_name( $post ) ), 0, 3 ) : sp_team_short_name( $post );
+		return $forced ? sp_substr( sp_strtoupper( sp_team_short_name( $post ) ), 0, 3 ) : sp_team_short_name( $post );
 	}
 }
 
diff --git a/includes/sp-core-functions.php b/includes/sp-core-functions.php
index 4a9949f6..596a3aa4 100644
--- a/includes/sp-core-functions.php
+++ b/includes/sp-core-functions.php
@@ -123,6 +123,22 @@ function sp_locate_template( $template_name, $template_path = '', $default_path
 	return apply_filters('sportspress_locate_template', $template, $template_name, $template_path);
 }
 
+function sp_substr( $string = '' ) {
+	if ( function_exists( 'mb_substr' ) ) {
+		return mb_substr( $string );
+	} else {
+		return substr( $string );
+	}
+}
+
+function sp_strtoupper( $string = '' ) {
+	if ( function_exists( 'mb_strtoupper' ) ) {
+		return mb_strtoupper( $string );
+	} else {
+		return strtoupper( $string );
+	}
+}
+
 /**
  * Get the timezone string.
  *
@@ -152,7 +168,7 @@ function sp_get_timezone() {
 
 /* deprecated functions below */
 
-if( !function_exists( 'date_diff' ) ) {
+if ( !function_exists( 'date_diff' ) ) {
 	class DateInterval {
 		public $y;
 		public $m;