diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4ec037e..30339f8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,12 +7,14 @@
 ## Unreleased
 ### Changed
 - **BC BREAK** | `UserRecommendation` now returns new format of response in `->getData()`, which is a list of `stdClass` instances.
+- **BC BREAK** | `UserRecommendation` does not have default filter (was previously set to: `valid_to >= NOW`).
 
 ### Fixed
 - Exceptions occurring during async request now generate rejected promise (as they should) and are no longer thrown directly.
 
 ### Added
 - `UserRecommendation` now sends which item properties should be returned alongside with item_ids.
+- **BC BREAK** | `UserRecommendation` now uses MQL query language by default for filtering.
 
 ## 1.6.0 - 2018-06-01
 ### Added
diff --git a/README.md b/README.md
index f4f6b1a..28f3ed5 100644
--- a/README.md
+++ b/README.md
@@ -184,7 +184,7 @@ You can also set more granular options of the recommendation command:
 
 ```php
 $recommendation = UserRecommendation::create('user-id', 5, 'test-scenario', 1.0, 3600);
-$recommendation->setFilters(['valid_to >= NOW']) // Note this filter is present by default
+$recommendation->setFilters(['for_recommendation = 1'])
     ->setMinimalRelevance(UserRecommendation::MINIMAL_RELEVANCE_HIGH)
     ->enableHardRotation();
 
diff --git a/src/Model/Command/UserRecommendation.php b/src/Model/Command/UserRecommendation.php
index d52d313..949076e 100644
--- a/src/Model/Command/UserRecommendation.php
+++ b/src/Model/Command/UserRecommendation.php
@@ -12,6 +12,8 @@ class UserRecommendation extends AbstractCommand implements UserAwareInterface
     public const MINIMAL_RELEVANCE_LOW = 'low';
     public const MINIMAL_RELEVANCE_MEDIUM = 'medium';
     public const MINIMAL_RELEVANCE_HIGH = 'high';
+    public const FILTER_TYPE_RGX = 'rgx';
+    public const FILTER_TYPE_MQL = 'mql';
 
     /** @var string */
     protected $filterOperator = 'and';
@@ -30,7 +32,9 @@ class UserRecommendation extends AbstractCommand implements UserAwareInterface
     /** @var string */
     private $minimalRelevance = self::MINIMAL_RELEVANCE_LOW;
     /** @var string[] */
-    private $filters = ['valid_to >= NOW'];
+    private $filters = [];
+    /** @var string */
+    private $filterType = self::FILTER_TYPE_MQL;
     /** @var string|null */
     private $modelName = null;
     /** @var string[] */
@@ -109,7 +113,7 @@ public function setMinimalRelevance(string $minimalRelevance): self
     }
 
     /**
-     * Add a filter to already added filters (including the default filter).
+     * Add a filter(s) to recommendation request. This can be called multiple times.
      *
      * @return $this
      */
@@ -121,7 +125,7 @@ public function addFilter(string $filter): self
     }
 
     /**
-     * Overwrite all filters by custom one. Note this will override also the default filter.
+     * Overwrite all filters by custom one.
      *
      * @return $this
      */
@@ -134,6 +138,22 @@ public function setFilters(array $filters): self
         return $this;
     }
 
+    /**
+     * Specify the filter type being used.
+     */
+    public function setFilterType(string $filterType): self
+    {
+        Assertion::typeIdentifier($filterType);
+        Assertion::choice(
+            $filterType,
+            [static::FILTER_TYPE_RGX, static::FILTER_TYPE_MQL]
+        );
+
+        $this->filterType = $filterType;
+
+        return $this;
+    }
+
     /**
      * Specify which item property you want returned.
      */
@@ -236,9 +256,14 @@ protected function getCommandParameters(): array
             'hard_rotation' => $this->hardRotation,
             'min_relevance' => $this->minimalRelevance,
             'filter' => $this->assembleFiltersString(),
+            'filter_type' => $this->filterType,
             'properties' => $this->responseProperties,
         ];
 
+        if ($this->filterType === self::FILTER_TYPE_RGX) {
+            unset($parameters['filter_type']);
+        }
+
         if ($this->modelName !== null) {
             $parameters['model_name'] = $this->modelName;
         }
diff --git a/tests/unit/Model/Command/UserRecommendationTest.php b/tests/unit/Model/Command/UserRecommendationTest.php
index dfe475f..e053183 100644
--- a/tests/unit/Model/Command/UserRecommendationTest.php
+++ b/tests/unit/Model/Command/UserRecommendationTest.php
@@ -23,7 +23,8 @@ public function shouldBeInstantiableViaNamedConstructorWithDefaultValues(): void
                     'rotation_time' => 3600,
                     'hard_rotation' => false,
                     'min_relevance' => UserRecommendation::MINIMAL_RELEVANCE_LOW,
-                    'filter' => 'valid_to >= NOW',
+                    'filter' => '',
+                    'filter_type' => UserRecommendation::FILTER_TYPE_MQL,
                     'properties' => [],
                     // intentionally no model name ==> should be absent when not used
                 ],
@@ -48,6 +49,7 @@ public function shouldUseCustomParameters(): void
         $command->setMinimalRelevance(UserRecommendation::MINIMAL_RELEVANCE_HIGH)
             ->enableHardRotation()
             ->setFilters(['foo = bar', 'baz = ban'])
+            ->setFilterType(UserRecommendation::FILTER_TYPE_RGX)
             ->setModelName($modelName);
 
         $this->assertInstanceOf(UserRecommendation::class, $command);
@@ -63,6 +65,7 @@ public function shouldUseCustomParameters(): void
                     'hard_rotation' => true,
                     'min_relevance' => UserRecommendation::MINIMAL_RELEVANCE_HIGH,
                     'filter' => 'foo = bar and baz = ban',
+                    // when a filter type is RGX, the parameter is absent.
                     'properties' => [],
                     'model_name' => $modelName,
                 ],
@@ -72,19 +75,19 @@ public function shouldUseCustomParameters(): void
     }
 
     /** @test */
-    public function shouldAssembleFilters(): void
+    public function shouldAssembleLegacyRgxFilters(): void
     {
         $command = UserRecommendation::create('user-id', 333, 'test-scenario', 1.0, 3600);
 
         // Default filter
-        $this->assertSame('valid_to >= NOW', $command->jsonSerialize()['parameters']['filter']);
+        $this->assertSame('', $command->jsonSerialize()['parameters']['filter']);
 
         // Add custom filters to the default one
         $command->addFilter('foo = bar')
             ->addFilter('bar = baz');
 
         $this->assertSame(
-            'valid_to >= NOW and foo = bar and bar = baz',
+            'foo = bar and bar = baz',
             $command->jsonSerialize()['parameters']['filter']
         );
 
@@ -94,6 +97,38 @@ public function shouldAssembleFilters(): void
         $this->assertSame('my_filter = 1 and other_filter = foo', $command->jsonSerialize()['parameters']['filter']);
     }
 
+    /** @test */
+    public function shouldAssembleMqlFilters(): void
+    {
+        $command = UserRecommendation::create('user-id', 333, 'test-scenario', 1.0, 3600);
+
+        // Default filter
+        $this->assertSame('', $command->jsonSerialize()['parameters']['filter']);
+
+        // Add custom filters to the default one
+        $command->addFilter("first_string_property = 'bar'")
+            ->addFilter("second_string_property LIKE 'bar%'")
+            ->addFilter("third_string_property NOT LIKE '%bar'")
+            ->addFilter('bool_property = true')
+            ->addFilter('nullable_property IS NULL')
+            ->addFilter("'some_value' in set_property");
+
+        $this->assertSame(
+            "first_string_property = 'bar' and " .
+                "second_string_property LIKE 'bar%' and " .
+                "third_string_property NOT LIKE '%bar' and " .
+                'bool_property = true and ' .
+                'nullable_property IS NULL and ' .
+                "'some_value' in set_property",
+            $command->jsonSerialize()['parameters']['filter']
+        );
+
+        // Overwrite all filters
+        $command->setFilters(['my_filter = 1', 'other_filter IS NULL']);
+
+        $this->assertSame('my_filter = 1 and other_filter IS NULL', $command->jsonSerialize()['parameters']['filter']);
+    }
+
     /** @test */
     public function shouldAllowModificationOfResponseProperties(): void
     {