diff --git a/UPGRADE b/UPGRADE
index ded528df..3f9d10c1 100644
--- a/UPGRADE
+++ b/UPGRADE
@@ -265,6 +265,9 @@ OTHER CHANGES:
 70. Added phone outbound alt caller ID to allow for phone-dialed calls to use
 	a separate CID number when dialing through a specific context
 
+71. Added display of admin change differences to last change on the change
+	detail page
+
 
 
 
diff --git a/www/vicidial/admin.php b/www/vicidial/admin.php
index e1b415c1..213d5bf1 100644
--- a/www/vicidial/admin.php
+++ b/www/vicidial/admin.php
@@ -3822,12 +3822,13 @@ else
 # 160514-1437 - Added ofcom_uk_drop_calc option
 # 160517-1927 - formatting fixes
 # 160602-1450 - Hiding email group settings that are not needed
+# 160611-2230 - Added diff to last change on admin change detail display
 #
 
 # make sure you have added a user to the vicidial_users MySQL table with at least user_level 9 to access this page the first time
 
-$admin_version = '2.12-558a';
-$build = '160602-1450';
+$admin_version = '2.12-559a';
+$build = '160611-2230';
 
 $STARTtime = date("U");
 $SQLdate = date("Y-m-d H:i:s");
@@ -36097,10 +36098,37 @@ if ($ADD==730000000000000)
 			echo "<TD ALIGN=RIGHT><B><FONT FACE=\"Arial,Helvetica\" size=2>"._QXZ("NOTES").": </B></TD>";
 			echo "<TD ALIGN=LEFT><FONT FACE=\"Arial,Helvetica\" size=1>$row[8]</TD>";
 			echo "</TR><TR>\n";
+			$new_sql = $row[9];
 			$row[9] = preg_replace('/\',/i', '\' ,',$row[9]);
 			$row[9] = preg_replace("/\|/","<BR>",$row[9]);
 			echo "<TD ALIGN=RIGHT><B><FONT FACE=\"Arial,Helvetica\" size=2>"._QXZ("SQL").": </B></TD>";
 			echo "<TD ALIGN=LEFT width=700><p style=\"width: 700; text-wrap: normal; word-wrap: break-word\"><FONT FACE=\"Arial,Helvetica\" size=1>$row[9]</TD>";
+
+			$stmt="SELECT admin_log_id,event_date,val.user,ip_address,event_section,event_type,record_id,event_code,event_notes,event_sql,full_name,val.user_group from vicidial_admin_log val, vicidial_users vu where event_section='$row[4]' and event_type='$row[5]' and record_id='$row[6]' and event_code='$row[7]' and admin_log_id < $row[0] and val.user=vu.user $valLOGadmin_viewable_groupsSQL order by admin_log_id desc;";
+			if ($DB > 0) {echo "$stmt\n";}
+			$rslt=mysql_to_mysqli($stmt, $link);
+			$last_to_print = mysqli_num_rows($rslt);
+
+			if ($last_to_print > 0)
+				{
+				$rowx=mysqli_fetch_row($rslt);
+				echo "</TR><TR>\n";
+				echo "<TD ALIGN=CENTER COLSPAN=2><B><FONT FACE=\"Arial,Helvetica\" size=2><BR>"._QXZ("DIFF TO LAST CHANGE")."<BR>"._QXZ("ID").": <a href=\"$PHP_SELF?ADD=730000000000000&stage=$rowx[0]\">$rowx[0]</a> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;"._QXZ("DATE TIME").": $rowx[1] &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;"._QXZ("USER").": $rowx[2]</B></TD></TR>";
+				echo "<TR><TD ALIGN=LEFT COLSPAN=2>";
+
+				// include the Diff class
+				require_once './class.Diff.php';
+
+				$new_sql = preg_replace('/\',/i', '\' ,',$new_sql);
+				$new_sql = preg_replace('/ ,/', "\n",$new_sql);
+				$rowx[9] = preg_replace('/\',/i', '\' ,',$rowx[9]);
+				$rowx[9] = preg_replace('/ ,/', "\n",$rowx[9]);
+
+				// output the result of comparing two files as HTML
+				echo Diff::toTable(Diff::compare($rowx[9], $new_sql));
+				}
+
+			echo "</TD>";
 			echo "</TR>\n";
 			echo "</TABLE><BR><BR>\n";
 			echo "\n";
diff --git a/www/vicidial/admin_header.php b/www/vicidial/admin_header.php
index 4118872f..baa95fdd 100644
--- a/www/vicidial/admin_header.php
+++ b/www/vicidial/admin_header.php
@@ -64,6 +64,7 @@
 # 160404-0934 - design changes
 # 160429-1014 - Added admin_row_click option
 # 160507-2324 - Added screen colors section
+# 160611-2229 - Added style for diff on admin changes
 #
 
 
@@ -1245,6 +1246,54 @@ echo "</script>\n";
 
 <style type="text/css">
 <!--
+
+
+<?php
+
+if ($ADD == '730000000000000')
+{
+?>
+
+.diff table{
+margin          : 1px 1px 1px 1px;
+border-collapse : collapse;
+border-spacing  : 0;
+}
+
+.diff td{
+vertical-align : top;
+font-family    : monospace;
+font-size      : 9;
+}
+.diff span{
+display:block;
+min-height:1pm;
+margin-top:-1px;
+padding:1px 1px 1px 1px;
+}
+
+* html .diff span{
+height:1px;
+}
+
+.diff span:first-child{
+margin-top:1px;
+}
+
+.diffDeleted span{
+border:1px solid rgb(255,51,0);
+background:rgb(255,173,153);
+}
+
+.diffInserted span{
+border:1px solid rgb(51,204,51);
+background:rgb(102,255,51);
+}
+
+<?php
+}
+?>
+
 .auraltext
 	{
 	position: absolute;
@@ -1320,6 +1369,7 @@ echo "</script>\n";
 	{
 
 -->
+
 </style>
 
 <?php
diff --git a/www/vicidial/class.Diff.php b/www/vicidial/class.Diff.php
new file mode 100644
index 00000000..04b4d596
--- /dev/null
+++ b/www/vicidial/class.Diff.php
@@ -0,0 +1,386 @@
+<?php
+
+/*
+
+class.Diff.php
+
+A class containing a diff implementation
+
+Created by Stephen Morley - http://stephenmorley.org/ - and released under the
+terms of the CC0 1.0 Universal legal code:
+
+http://creativecommons.org/publicdomain/zero/1.0/legalcode
+
+*/
+
+// A class containing functions for computing diffs and formatting the output.
+class Diff{
+
+  // define the constants
+  const UNMODIFIED = 0;
+  const DELETED    = 1;
+  const INSERTED   = 2;
+
+  /* Returns the diff for two strings. The return value is an array, each of
+   * whose values is an array containing two values: a line (or character, if
+   * $compareCharacters is true), and one of the constants DIFF::UNMODIFIED (the
+   * line or character is in both strings), DIFF::DELETED (the line or character
+   * is only in the first string), and DIFF::INSERTED (the line or character is
+   * only in the second string). The parameters are:
+   *
+   * $string1           - the first string
+   * $string2           - the second string
+   * $compareCharacters - true to compare characters, and false to compare
+   *                      lines; this optional parameter defaults to false
+   */
+  public static function compare(
+      $string1, $string2, $compareCharacters = false){
+
+    // initialise the sequences and comparison start and end positions
+    $start = 0;
+    if ($compareCharacters){
+      $sequence1 = $string1;
+      $sequence2 = $string2;
+      $end1 = strlen($string1) - 1;
+      $end2 = strlen($string2) - 1;
+    }else{
+      $sequence1 = preg_split('/\R/', $string1);
+      $sequence2 = preg_split('/\R/', $string2);
+      $end1 = count($sequence1) - 1;
+      $end2 = count($sequence2) - 1;
+    }
+
+    // skip any common prefix
+    while ($start <= $end1 && $start <= $end2
+        && $sequence1[$start] == $sequence2[$start]){
+      $start ++;
+    }
+
+    // skip any common suffix
+    while ($end1 >= $start && $end2 >= $start
+        && $sequence1[$end1] == $sequence2[$end2]){
+      $end1 --;
+      $end2 --;
+    }
+
+    // compute the table of longest common subsequence lengths
+    $table = self::computeTable($sequence1, $sequence2, $start, $end1, $end2);
+
+    // generate the partial diff
+    $partialDiff =
+        self::generatePartialDiff($table, $sequence1, $sequence2, $start);
+
+    // generate the full diff
+    $diff = array();
+    for ($index = 0; $index < $start; $index ++){
+      $diff[] = array($sequence1[$index], self::UNMODIFIED);
+    }
+    while (count($partialDiff) > 0) $diff[] = array_pop($partialDiff);
+    for ($index = $end1 + 1;
+        $index < ($compareCharacters ? strlen($sequence1) : count($sequence1));
+        $index ++){
+      $diff[] = array($sequence1[$index], self::UNMODIFIED);
+    }
+
+    // return the diff
+    return $diff;
+
+  }
+
+  /* Returns the diff for two files. The parameters are:
+   *
+   * $file1             - the path to the first file
+   * $file2             - the path to the second file
+   * $compareCharacters - true to compare characters, and false to compare
+   *                      lines; this optional parameter defaults to false
+   */
+  public static function compareFiles(
+      $file1, $file2, $compareCharacters = false){
+
+    // return the diff of the files
+    return self::compare(
+        file_get_contents($file1),
+        file_get_contents($file2),
+        $compareCharacters);
+
+  }
+
+  /* Returns the table of longest common subsequence lengths for the specified
+   * sequences. The parameters are:
+   *
+   * $sequence1 - the first sequence
+   * $sequence2 - the second sequence
+   * $start     - the starting index
+   * $end1      - the ending index for the first sequence
+   * $end2      - the ending index for the second sequence
+   */
+  private static function computeTable(
+      $sequence1, $sequence2, $start, $end1, $end2){
+
+    // determine the lengths to be compared
+    $length1 = $end1 - $start + 1;
+    $length2 = $end2 - $start + 1;
+
+    // initialise the table
+    $table = array(array_fill(0, $length2 + 1, 0));
+
+    // loop over the rows
+    for ($index1 = 1; $index1 <= $length1; $index1 ++){
+
+      // create the new row
+      $table[$index1] = array(0);
+
+      // loop over the columns
+      for ($index2 = 1; $index2 <= $length2; $index2 ++){
+
+        // store the longest common subsequence length
+        if ($sequence1[$index1 + $start - 1]
+            == $sequence2[$index2 + $start - 1]){
+          $table[$index1][$index2] = $table[$index1 - 1][$index2 - 1] + 1;
+        }else{
+          $table[$index1][$index2] =
+              max($table[$index1 - 1][$index2], $table[$index1][$index2 - 1]);
+        }
+
+      }
+    }
+
+    // return the table
+    return $table;
+
+  }
+
+  /* Returns the partial diff for the specificed sequences, in reverse order.
+   * The parameters are:
+   *
+   * $table     - the table returned by the computeTable function
+   * $sequence1 - the first sequence
+   * $sequence2 - the second sequence
+   * $start     - the starting index
+   */
+  private static function generatePartialDiff(
+      $table, $sequence1, $sequence2, $start){
+
+    //  initialise the diff
+    $diff = array();
+
+    // initialise the indices
+    $index1 = count($table) - 1;
+    $index2 = count($table[0]) - 1;
+
+    // loop until there are no items remaining in either sequence
+    while ($index1 > 0 || $index2 > 0){
+
+      // check what has happened to the items at these indices
+      if ($index1 > 0 && $index2 > 0
+          && $sequence1[$index1 + $start - 1]
+              == $sequence2[$index2 + $start - 1]){
+
+        // update the diff and the indices
+        $diff[] = array($sequence1[$index1 + $start - 1], self::UNMODIFIED);
+        $index1 --;
+        $index2 --;
+
+      }elseif ($index2 > 0
+          && $table[$index1][$index2] == $table[$index1][$index2 - 1]){
+
+        // update the diff and the indices
+        $diff[] = array($sequence2[$index2 + $start - 1], self::INSERTED);
+        $index2 --;
+
+      }else{
+
+        // update the diff and the indices
+        $diff[] = array($sequence1[$index1 + $start - 1], self::DELETED);
+        $index1 --;
+
+      }
+
+    }
+
+    // return the diff
+    return $diff;
+
+  }
+
+  /* Returns a diff as a string, where unmodified lines are prefixed by '  ',
+   * deletions are prefixed by '- ', and insertions are prefixed by '+ '. The
+   * parameters are:
+   *
+   * $diff      - the diff array
+   * $separator - the separator between lines; this optional parameter defaults
+   *              to "\n"
+   */
+  public static function toString($diff, $separator = "\n"){
+
+    // initialise the string
+    $string = '';
+
+    // loop over the lines in the diff
+    foreach ($diff as $line){
+
+      // extend the string with the line
+      switch ($line[1]){
+        case self::UNMODIFIED : $string .= '  ' . $line[0];break;
+        case self::DELETED    : $string .= '- ' . $line[0];break;
+        case self::INSERTED   : $string .= '+ ' . $line[0];break;
+      }
+
+      // extend the string with the separator
+      $string .= $separator;
+
+    }
+
+    // return the string
+    return $string;
+
+  }
+
+  /* Returns a diff as an HTML string, where unmodified lines are contained
+   * within 'span' elements, deletions are contained within 'del' elements, and
+   * insertions are contained within 'ins' elements. The parameters are:
+   *
+   * $diff      - the diff array
+   * $separator - the separator between lines; this optional parameter defaults
+   *              to '<br>'
+   */
+  public static function toHTML($diff, $separator = '<br>'){
+
+    // initialise the HTML
+    $html = '';
+
+    // loop over the lines in the diff
+    foreach ($diff as $line){
+
+      // extend the HTML with the line
+      switch ($line[1]){
+        case self::UNMODIFIED : $element = 'span'; break;
+        case self::DELETED    : $element = 'del';  break;
+        case self::INSERTED   : $element = 'ins';  break;
+      }
+      $html .=
+          '<' . $element . '>'
+          . htmlspecialchars($line[0])
+          . '</' . $element . '>';
+
+      // extend the HTML with the separator
+      $html .= $separator;
+
+    }
+
+    // return the HTML
+    return $html;
+
+  }
+
+  /* Returns a diff as an HTML table. The parameters are:
+   *
+   * $diff        - the diff array
+   * $indentation - indentation to add to every line of the generated HTML; this
+   *                optional parameter defaults to ''
+   * $separator   - the separator between lines; this optional parameter
+   *                defaults to '<br>'
+   */
+  public static function toTable($diff, $indentation = '', $separator = ''){
+
+    // initialise the HTML
+    $html = $indentation . "<table class=\"diff\">\n";
+
+    // loop over the lines in the diff
+    $index = 0;
+    while ($index < count($diff)){
+
+      // determine the line type
+      switch ($diff[$index][1]){
+
+        // display the content on the left and right
+        case self::UNMODIFIED:
+          $leftCell =
+              self::getCellContent(
+                  $diff, $indentation, $separator, $index, self::UNMODIFIED);
+          $rightCell = $leftCell;
+          break;
+
+        // display the deleted on the left and inserted content on the right
+        case self::DELETED:
+          $leftCell =
+              self::getCellContent(
+                  $diff, $indentation, $separator, $index, self::DELETED);
+          $rightCell =
+              self::getCellContent(
+                  $diff, $indentation, $separator, $index, self::INSERTED);
+          break;
+
+        // display the inserted content on the right
+        case self::INSERTED:
+          $leftCell = '';
+          $rightCell =
+              self::getCellContent(
+                  $diff, $indentation, $separator, $index, self::INSERTED);
+          break;
+
+      }
+
+      // extend the HTML with the new row
+      $html .=
+          $indentation
+          . "  <tr>\n"
+          . $indentation
+          . '    <td class="diff'
+          . ($leftCell == $rightCell
+              ? 'Unmodified'
+              : ($leftCell == '' ? 'Blank' : 'Deleted'))
+          . '">'
+          . $leftCell
+          . "</td>\n"
+          . $indentation
+          . '    <td class="diff'
+          . ($leftCell == $rightCell
+              ? 'Unmodified'
+              : ($rightCell == '' ? 'Blank' : 'Inserted'))
+          . '">'
+          . $rightCell
+          . "</td>\n"
+          . $indentation
+          . "  </tr>\n";
+
+    }
+
+    // return the HTML
+    return $html . $indentation . "</table>\n";
+
+  }
+
+  /* Returns the content of the cell, for use in the toTable function. The
+   * parameters are:
+   *
+   * $diff        - the diff array
+   * $indentation - indentation to add to every line of the generated HTML
+   * $separator   - the separator between lines
+   * $index       - the current index, passes by reference
+   * $type        - the type of line
+   */
+  private static function getCellContent(
+      $diff, $indentation, $separator, &$index, $type){
+
+    // initialise the HTML
+    $html = '';
+
+    // loop over the matching lines, adding them to the HTML
+    while ($index < count($diff) && $diff[$index][1] == $type){
+      $html .=
+          '<span>'
+          . htmlspecialchars($diff[$index][0])
+          . '</span>'
+          . $separator;
+      $index ++;
+    }
+
+    // return the HTML
+    return $html;
+
+  }
+
+}
+
+?>