diff --git a/lib/mustache/readme_moodle.txt b/lib/mustache/readme_moodle.txt
index 912fc862690..e443e5893ce 100644
--- a/lib/mustache/readme_moodle.txt
+++ b/lib/mustache/readme_moodle.txt
@@ -10,6 +10,8 @@ Delete phpunit.xml.dist
 
 Delete hidden files ".*"
 
+Delete hidden directories ".git"
+
 Delete folder "bin"
 
 Delete folder "vendor"
@@ -17,3 +19,7 @@ Delete folder "vendor"
 Delete composer.json
 
 Copy into this folder, and update this readme to cover any changes.
+
+== 3.1 ==
+
+Update from version 2.9.0 to 2.10.0
diff --git a/lib/mustache/src/Mustache/Compiler.php b/lib/mustache/src/Mustache/Compiler.php
index 7d5c96b56ee..76e580c7f2b 100644
--- a/lib/mustache/src/Mustache/Compiler.php
+++ b/lib/mustache/src/Mustache/Compiler.php
@@ -328,7 +328,7 @@ class Mustache_Compiler
             $buffer = \'\';
             if (%s) {
                 $source = %s;
-                $result = call_user_func($value, $source, $this->lambdaHelper);
+                $result = call_user_func($value, $source, %s);
                 if (strpos($result, \'{{\') === false) {
                     $buffer .= $result;
                 } else {
@@ -370,15 +370,18 @@ class Mustache_Compiler
         $callable = $this->getCallable();
 
         if ($otag !== '{{' || $ctag !== '}}') {
-            $delims = ', ' . var_export(sprintf('{{= %s %s =}}', $otag, $ctag), true);
+            $delimTag = var_export(sprintf('{{= %s %s =}}', $otag, $ctag), true);
+            $helper = sprintf('$this->lambdaHelper->withDelimiters(%s)', $delimTag);
+            $delims = ', ' . $delimTag;
         } else {
+            $helper = '$this->lambdaHelper';
             $delims = '';
         }
 
         $key = ucfirst(md5($delims . "\n" . $source));
 
         if (!isset($this->sections[$key])) {
-            $this->sections[$key] = sprintf($this->prepare(self::SECTION), $key, $callable, $source, $delims, $this->walk($nodes, 2));
+            $this->sections[$key] = sprintf($this->prepare(self::SECTION), $key, $callable, $source, $helper, $delims, $this->walk($nodes, 2));
         }
 
         if ($arg === true) {
@@ -495,7 +498,7 @@ class Mustache_Compiler
     }
 
     const VARIABLE = '
-        $value = $this->resolveValue($context->%s(%s), $context, $indent);%s
+        $value = $this->resolveValue($context->%s(%s), $context);%s
         $buffer .= %s%s;
     ';
 
diff --git a/lib/mustache/src/Mustache/Engine.php b/lib/mustache/src/Mustache/Engine.php
index 08bcc810f3d..fe119121895 100644
--- a/lib/mustache/src/Mustache/Engine.php
+++ b/lib/mustache/src/Mustache/Engine.php
@@ -23,7 +23,7 @@
  */
 class Mustache_Engine
 {
-    const VERSION        = '2.9.0';
+    const VERSION        = '2.10.0';
     const SPEC_VERSION   = '1.1.2';
 
     const PRAGMA_FILTERS      = 'FILTERS';
diff --git a/lib/mustache/src/Mustache/LambdaHelper.php b/lib/mustache/src/Mustache/LambdaHelper.php
index de48fd63335..cb8e96698fa 100644
--- a/lib/mustache/src/Mustache/LambdaHelper.php
+++ b/lib/mustache/src/Mustache/LambdaHelper.php
@@ -20,17 +20,20 @@ class Mustache_LambdaHelper
 {
     private $mustache;
     private $context;
+    private $delims;
 
     /**
      * Mustache Lambda Helper constructor.
      *
      * @param Mustache_Engine  $mustache Mustache engine instance.
      * @param Mustache_Context $context  Rendering context.
+     * @param string           $delims   Optional custom delimiters, in the format `{{= <% %> =}}`. (default: null)
      */
-    public function __construct(Mustache_Engine $mustache, Mustache_Context $context)
+    public function __construct(Mustache_Engine $mustache, Mustache_Context $context, $delims = null)
     {
         $this->mustache = $mustache;
         $this->context  = $context;
+        $this->delims   = $delims;
     }
 
     /**
@@ -43,7 +46,31 @@ class Mustache_LambdaHelper
     public function render($string)
     {
         return $this->mustache
-            ->loadLambda((string) $string)
+            ->loadLambda((string) $string, $this->delims)
             ->renderInternal($this->context);
     }
+
+    /**
+     * Render a string as a Mustache template with the current rendering context.
+     *
+     * @param string $string
+     *
+     * @return string Rendered template
+     */
+    public function __invoke($string)
+    {
+        return $this->render($string);
+    }
+
+    /**
+     * Get a Lambda Helper with custom delimiters.
+     *
+     * @param string $delims Custom delimiters, in the format `{{= <% %> =}}`.
+     *
+     * @return Mustache_LambdaHelper
+     */
+    public function withDelimiters($delims)
+    {
+        return new self($this->mustache, $this->context, $delims);
+    }
 }
diff --git a/lib/mustache/src/Mustache/Template.php b/lib/mustache/src/Mustache/Template.php
index 91074c448e3..f2d198f22c3 100644
--- a/lib/mustache/src/Mustache/Template.php
+++ b/lib/mustache/src/Mustache/Template.php
@@ -164,16 +164,15 @@ abstract class Mustache_Template
      *
      * @param mixed            $value
      * @param Mustache_Context $context
-     * @param string           $indent
      *
      * @return string
      */
-    protected function resolveValue($value, Mustache_Context $context, $indent = '')
+    protected function resolveValue($value, Mustache_Context $context)
     {
         if (($this->strictCallables ? is_object($value) : !is_string($value)) && is_callable($value)) {
             return $this->mustache
                 ->loadLambda((string) call_user_func($value))
-                ->renderInternal($context, $indent);
+                ->renderInternal($context);
         }
 
         return $value;
diff --git a/lib/thirdpartylibs.xml b/lib/thirdpartylibs.xml
index df2969fe83f..382f190e9f0 100644
--- a/lib/thirdpartylibs.xml
+++ b/lib/thirdpartylibs.xml
@@ -255,7 +255,7 @@
     <location>mustache</location>
     <name>Mustache</name>
     <license>MIT</license>
-    <version>2.9.0</version>
+    <version>2.10.0</version>
   </library>
   <library>
     <location>amd/src/mustache.js</location>