diff --git a/wp-admin/includes/class-ftp.php b/wp-admin/includes/class-ftp.php
index 60fb2a19f6..3bfa469d20 100644
--- a/wp-admin/includes/class-ftp.php
+++ b/wp-admin/includes/class-ftp.php
@@ -185,8 +185,8 @@ class ftp_base {
 			$lcount=count($lucifer);
 			if ($lcount<8) return '';
 			$b = array();
-			$b['isdir'] = $lucifer[0]{0} === "d";
-			$b['islink'] = $lucifer[0]{0} === "l";
+			$b['isdir'] = $lucifer[0][0] === "d";
+			$b['islink'] = $lucifer[0][0] === "l";
 			if ( $b['isdir'] )
 				$b['type'] = 'd';
 			elseif ( $b['islink'] )
diff --git a/wp-admin/includes/class-wp-filesystem-ftpext.php b/wp-admin/includes/class-wp-filesystem-ftpext.php
index 1a936cfd41..53b1899666 100644
--- a/wp-admin/includes/class-wp-filesystem-ftpext.php
+++ b/wp-admin/includes/class-wp-filesystem-ftpext.php
@@ -599,8 +599,8 @@ class WP_Filesystem_FTPext extends WP_Filesystem_Base {
 					return '';
 				}
 				$b           = array();
-				$b['isdir']  = $lucifer[0]{0} === 'd';
-				$b['islink'] = $lucifer[0]{0} === 'l';
+				$b['isdir']  = $lucifer[0][0] === 'd';
+				$b['islink'] = $lucifer[0][0] === 'l';
 				if ( $b['isdir'] ) {
 					$b['type'] = 'd';
 				} elseif ( $b['islink'] ) {
diff --git a/wp-admin/includes/class-wp-importer.php b/wp-admin/includes/class-wp-importer.php
index 96db3b4458..43a2038d03 100644
--- a/wp-admin/includes/class-wp-importer.php
+++ b/wp-admin/includes/class-wp-importer.php
@@ -307,7 +307,7 @@ function get_cli_args( $param, $required = false ) {
 			$last_arg = $key;
 		} elseif ( (bool) preg_match( '/^-([a-zA-Z0-9]+)/', $args[ $i ], $match ) ) {
 			for ( $j = 0, $jl = strlen( $match[1] ); $j < $jl; $j++ ) {
-				$key         = $match[1]{$j};
+				$key         = $match[1][ $j ];
 				$out[ $key ] = true;
 			}
 
diff --git a/wp-includes/class-json.php b/wp-includes/class-json.php
index a8c61c92e9..4e512f5c26 100644
--- a/wp-includes/class-json.php
+++ b/wp-includes/class-json.php
@@ -177,7 +177,7 @@ class Services_JSON
             return mb_convert_encoding($utf16, 'UTF-8', 'UTF-16');
         }
 
-        $bytes = (ord($utf16{0}) << 8) | ord($utf16{1});
+        $bytes = (ord($utf16[0]) << 8) | ord($utf16[1]);
 
         switch(true) {
             case ((0x7F & $bytes) == $bytes):
@@ -230,17 +230,17 @@ class Services_JSON
             case 2:
                 // return a UTF-16 character from a 2-byte UTF-8 char
                 // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
-                return chr(0x07 & (ord($utf8{0}) >> 2))
-                     . chr((0xC0 & (ord($utf8{0}) << 6))
-                         | (0x3F & ord($utf8{1})));
+                return chr(0x07 & (ord($utf8[0]) >> 2))
+                     . chr((0xC0 & (ord($utf8[0]) << 6))
+                         | (0x3F & ord($utf8[1])));
 
             case 3:
                 // return a UTF-16 character from a 3-byte UTF-8 char
                 // see: http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
-                return chr((0xF0 & (ord($utf8{0}) << 4))
-                         | (0x0F & (ord($utf8{1}) >> 2)))
-                     . chr((0xC0 & (ord($utf8{1}) << 6))
-                         | (0x7F & ord($utf8{2})));
+                return chr((0xF0 & (ord($utf8[0]) << 4))
+                         | (0x0F & (ord($utf8[1]) >> 2)))
+                     . chr((0xC0 & (ord($utf8[1]) << 6))
+                         | (0x7F & ord($utf8[2])));
         }
 
         // ignoring UTF-32 for now, sorry
@@ -323,7 +323,7 @@ class Services_JSON
                 */
                 for ($c = 0; $c < $strlen_var; ++$c) {
 
-                    $ord_var_c = ord($var{$c});
+                    $ord_var_c = ord($var[$c]);
 
                     switch (true) {
                         case $ord_var_c == 0x08:
@@ -346,12 +346,12 @@ class Services_JSON
                         case $ord_var_c == 0x2F:
                         case $ord_var_c == 0x5C:
                             // double quote, slash, slosh
-                            $ascii .= '\\'.$var{$c};
+                            $ascii .= '\\'.$var[$c];
                             break;
 
                         case (($ord_var_c >= 0x20) && ($ord_var_c <= 0x7F)):
                             // characters U-00000000 - U-0000007F (same as ASCII)
-                            $ascii .= $var{$c};
+                            $ascii .= $var[$c];
                             break;
 
                         case (($ord_var_c & 0xE0) == 0xC0):
@@ -363,7 +363,7 @@ class Services_JSON
                                 break;
                             }
                             
-                            $char = pack('C*', $ord_var_c, ord($var{$c + 1}));
+                            $char = pack('C*', $ord_var_c, ord($var[$c + 1]));
                             $c += 1;
                             $utf16 = $this->utf82utf16($char);
                             $ascii .= sprintf('\u%04s', bin2hex($utf16));
@@ -378,8 +378,8 @@ class Services_JSON
                             // characters U-00000800 - U-0000FFFF, mask 1110XXXX
                             // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
                             $char = pack('C*', $ord_var_c,
-                                         @ord($var{$c + 1}),
-                                         @ord($var{$c + 2}));
+                                         @ord($var[$c + 1]),
+                                         @ord($var[$c + 2]));
                             $c += 2;
                             $utf16 = $this->utf82utf16($char);
                             $ascii .= sprintf('\u%04s', bin2hex($utf16));
@@ -394,9 +394,9 @@ class Services_JSON
                             // characters U-00010000 - U-001FFFFF, mask 11110XXX
                             // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
                             $char = pack('C*', $ord_var_c,
-                                         ord($var{$c + 1}),
-                                         ord($var{$c + 2}),
-                                         ord($var{$c + 3}));
+                                         ord($var[$c + 1]),
+                                         ord($var[$c + 2]),
+                                         ord($var[$c + 3]));
                             $c += 3;
                             $utf16 = $this->utf82utf16($char);
                             $ascii .= sprintf('\u%04s', bin2hex($utf16));
@@ -411,10 +411,10 @@ class Services_JSON
                                 break;
                             }
                             $char = pack('C*', $ord_var_c,
-                                         ord($var{$c + 1}),
-                                         ord($var{$c + 2}),
-                                         ord($var{$c + 3}),
-                                         ord($var{$c + 4}));
+                                         ord($var[$c + 1]),
+                                         ord($var[$c + 2]),
+                                         ord($var[$c + 3]),
+                                         ord($var[$c + 4]));
                             $c += 4;
                             $utf16 = $this->utf82utf16($char);
                             $ascii .= sprintf('\u%04s', bin2hex($utf16));
@@ -429,11 +429,11 @@ class Services_JSON
                             // characters U-04000000 - U-7FFFFFFF, mask 1111110X
                             // see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
                             $char = pack('C*', $ord_var_c,
-                                         ord($var{$c + 1}),
-                                         ord($var{$c + 2}),
-                                         ord($var{$c + 3}),
-                                         ord($var{$c + 4}),
-                                         ord($var{$c + 5}));
+                                         ord($var[$c + 1]),
+                                         ord($var[$c + 2]),
+                                         ord($var[$c + 3]),
+                                         ord($var[$c + 4]),
+                                         ord($var[$c + 5]));
                             $c += 5;
                             $utf16 = $this->utf82utf16($char);
                             $ascii .= sprintf('\u%04s', bin2hex($utf16));
@@ -626,7 +626,7 @@ class Services_JSON
                     for ($c = 0; $c < $strlen_chrs; ++$c) {
 
                         $substr_chrs_c_2 = $this->substr8($chrs, $c, 2);
-                        $ord_chrs_c = ord($chrs{$c});
+                        $ord_chrs_c = ord($chrs[$c]);
 
                         switch (true) {
                             case $substr_chrs_c_2 == '\b':
@@ -656,7 +656,7 @@ class Services_JSON
                             case $substr_chrs_c_2 == '\\/':
                                 if (($delim == '"' && $substr_chrs_c_2 != '\\\'') ||
                                    ($delim == "'" && $substr_chrs_c_2 != '\\"')) {
-                                    $utf8 .= $chrs{++$c};
+                                    $utf8 .= $chrs[++$c];
                                 }
                                 break;
 
@@ -669,7 +669,7 @@ class Services_JSON
                                 break;
 
                             case ($ord_chrs_c >= 0x20) && ($ord_chrs_c <= 0x7F):
-                                $utf8 .= $chrs{$c};
+                                $utf8 .= $chrs[$c];
                                 break;
 
                             case ($ord_chrs_c & 0xE0) == 0xC0:
@@ -716,7 +716,7 @@ class Services_JSON
                 } elseif (preg_match('/^\[.*\]$/s', $str) || preg_match('/^\{.*\}$/s', $str)) {
                     // array, or object notation
 
-                    if ($str{0} == '[') {
+                    if ($str[0] == '[') {
                         $stk = array(SERVICES_JSON_IN_ARR);
                         $arr = array();
                     } else {
@@ -755,7 +755,7 @@ class Services_JSON
                         $top = end($stk);
                         $substr_chrs_c_2 = $this->substr8($chrs, $c, 2);
 
-                        if (($c == $strlen_chrs) || (($chrs{$c} == ',') && ($top['what'] == SERVICES_JSON_SLICE))) {
+                        if (($c == $strlen_chrs) || (($chrs[$c] == ',') && ($top['what'] == SERVICES_JSON_SLICE))) {
                             // found a comma that is not inside a string, array, etc.,
                             // OR we've reached the end of the character list
                             $slice = $this->substr8($chrs, $top['where'], ($c - $top['where']));
@@ -796,12 +796,12 @@ class Services_JSON
 
                             }
 
-                        } elseif ((($chrs{$c} == '"') || ($chrs{$c} == "'")) && ($top['what'] != SERVICES_JSON_IN_STR)) {
+                        } elseif ((($chrs[$c] == '"') || ($chrs[$c] == "'")) && ($top['what'] != SERVICES_JSON_IN_STR)) {
                             // found a quote, and we are not inside a string
-                            array_push($stk, array('what' => SERVICES_JSON_IN_STR, 'where' => $c, 'delim' => $chrs{$c}));
+                            array_push($stk, array('what' => SERVICES_JSON_IN_STR, 'where' => $c, 'delim' => $chrs[$c]));
                             //print("Found start of string at {$c}\n");
 
-                        } elseif (($chrs{$c} == $top['delim']) &&
+                        } elseif (($chrs[$c] == $top['delim']) &&
                                  ($top['what'] == SERVICES_JSON_IN_STR) &&
                                  (($this->strlen8($this->substr8($chrs, 0, $c)) - $this->strlen8(rtrim($this->substr8($chrs, 0, $c), '\\'))) % 2 != 1)) {
                             // found a quote, we're in a string, and it's not escaped
@@ -810,24 +810,24 @@ class Services_JSON
                             array_pop($stk);
                             //print("Found end of string at {$c}: ".$this->substr8($chrs, $top['where'], (1 + 1 + $c - $top['where']))."\n");
 
-                        } elseif (($chrs{$c} == '[') &&
+                        } elseif (($chrs[$c] == '[') &&
                                  in_array($top['what'], array(SERVICES_JSON_SLICE, SERVICES_JSON_IN_ARR, SERVICES_JSON_IN_OBJ))) {
                             // found a left-bracket, and we are in an array, object, or slice
                             array_push($stk, array('what' => SERVICES_JSON_IN_ARR, 'where' => $c, 'delim' => false));
                             //print("Found start of array at {$c}\n");
 
-                        } elseif (($chrs{$c} == ']') && ($top['what'] == SERVICES_JSON_IN_ARR)) {
+                        } elseif (($chrs[$c] == ']') && ($top['what'] == SERVICES_JSON_IN_ARR)) {
                             // found a right-bracket, and we're in an array
                             array_pop($stk);
                             //print("Found end of array at {$c}: ".$this->substr8($chrs, $top['where'], (1 + $c - $top['where']))."\n");
 
-                        } elseif (($chrs{$c} == '{') &&
+                        } elseif (($chrs[$c] == '{') &&
                                  in_array($top['what'], array(SERVICES_JSON_SLICE, SERVICES_JSON_IN_ARR, SERVICES_JSON_IN_OBJ))) {
                             // found a left-brace, and we are in an array, object, or slice
                             array_push($stk, array('what' => SERVICES_JSON_IN_OBJ, 'where' => $c, 'delim' => false));
                             //print("Found start of object at {$c}\n");
 
-                        } elseif (($chrs{$c} == '}') && ($top['what'] == SERVICES_JSON_IN_OBJ)) {
+                        } elseif (($chrs[$c] == '}') && ($top['what'] == SERVICES_JSON_IN_OBJ)) {
                             // found a right-brace, and we're in an object
                             array_pop($stk);
                             //print("Found end of object at {$c}: ".$this->substr8($chrs, $top['where'], (1 + $c - $top['where']))."\n");
diff --git a/wp-includes/class-pop3.php b/wp-includes/class-pop3.php
index 7416dd7001..9ad185698e 100644
--- a/wp-includes/class-pop3.php
+++ b/wp-includes/class-pop3.php
@@ -376,7 +376,7 @@ class POP3 {
         $line = fgets($fp,$buffer);
         while ( !preg_match('/^\.\r\n/',$line))
         {
-            if ( $line{0} == '.' ) { $line = substr($line,1); }
+            if ( $line[0] == '.' ) { $line = substr($line,1); }
             $MsgArray[$count] = $line;
             $count++;
             $line = fgets($fp,$buffer);
diff --git a/wp-includes/class-wp-editor.php b/wp-includes/class-wp-editor.php
index fb0a8eb80d..38e1871d4b 100644
--- a/wp-includes/class-wp-editor.php
+++ b/wp-includes/class-wp-editor.php
@@ -757,8 +757,8 @@ final class _WP_Editors {
 				$options .= $key . ':' . $val . ',';
 				continue;
 			} elseif ( ! empty( $value ) && is_string( $value ) && (
-				( '{' == $value{0} && '}' == $value{strlen( $value ) - 1} ) ||
-				( '[' == $value{0} && ']' == $value{strlen( $value ) - 1} ) ||
+				( '{' == $value[0] && '}' == $value[ strlen( $value ) - 1 ] ) ||
+				( '[' == $value[0] && ']' == $value[ strlen( $value ) - 1 ] ) ||
 				preg_match( '/^\(?function ?\(/', $value ) ) ) {
 
 				$options .= $key . ':' . $value . ',';
diff --git a/wp-includes/script-loader.php b/wp-includes/script-loader.php
index ec412c0969..5dc797425e 100644
--- a/wp-includes/script-loader.php
+++ b/wp-includes/script-loader.php
@@ -754,8 +754,8 @@ function wp_tinymce_inline_scripts() {
 			$init_obj .= $key . ':' . $val . ',';
 			continue;
 		} elseif ( ! empty( $value ) && is_string( $value ) && (
-			( '{' === $value{0} && '}' === $value{strlen( $value ) - 1} ) ||
-			( '[' === $value{0} && ']' === $value{strlen( $value ) - 1} ) ||
+			( '{' === $value[0] && '}' === $value[ strlen( $value ) - 1 ] ) ||
+			( '[' === $value[0] && ']' === $value[ strlen( $value ) - 1 ] ) ||
 			preg_match( '/^\(?function ?\(/', $value ) ) ) {
 			$init_obj .= $key . ':' . $value . ',';
 			continue;
diff --git a/wp-includes/version.php b/wp-includes/version.php
index a495ae860a..5609cfe2d6 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-alpha-45729';
+$wp_version = '5.3-alpha-45730';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.