diff --git a/.github/workflows/phpunit.yml b/.github/workflows/phpunit.yml
index e979b51a..f056a561 100644
--- a/.github/workflows/phpunit.yml
+++ b/.github/workflows/phpunit.yml
@@ -3,9 +3,9 @@ on:
   push:
     branches:
       - master
-    pull_request:
-      branches:
-        - master
+  pull_request:
+    branches:
+      - master
 jobs:
   run-tests:
     name: PHP ${{ matrix.php-versions }}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 87a8f241..d280ad3a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,10 +25,11 @@ All notable changes to this project will be documented in this file, in reverse
 ### Removed
 
 - Deprecated `Api::VERSION` constant
+- Removed dependency on APC-BC Extension
 
 ### Fixed
 
-- Nothing.
+- [#18](https://github.com/netglue/prismic-php-kit/pull/18) correctly serializes booleans for predicates when querying the api.
 
 ## 4.3.0 - 2020-03-12
 
diff --git a/src/Prismic/SimplePredicate.php b/src/Prismic/SimplePredicate.php
index 09135920..d707be15 100644
--- a/src/Prismic/SimplePredicate.php
+++ b/src/Prismic/SimplePredicate.php
@@ -5,6 +5,7 @@
 
 use function implode;
 use function is_array;
+use function is_bool;
 use function is_string;
 
 class SimplePredicate implements Predicate
@@ -55,6 +56,10 @@ private function serializeField($value) : string
             return '"' . $value . '"';
         }
 
+        if (is_bool($value)) {
+            return $value ? 'true' : 'false';
+        }
+
         if (is_array($value)) {
             $fields = [];
             foreach ($value as $elt) {
diff --git a/tests/Prismic/PredicatesTest.php b/tests/Prismic/PredicatesTest.php
index e97aab6f..6ce5abba 100644
--- a/tests/Prismic/PredicatesTest.php
+++ b/tests/Prismic/PredicatesTest.php
@@ -308,4 +308,12 @@ public function testGeopointNear() : void
         $p = Predicates::near('my.store.coordinates', 40.689757, -74.0451453, 15);
         $this->assertEquals('[:d = geopoint.near(my.store.coordinates, 40.689757, -74.0451453, 15)]', $p->q());
     }
+
+    public function testAtPredicateAcceptsBooleanValue() : void
+    {
+        $p = Predicates::at('my.doc.field', true);
+        $this->assertEquals('[:d = at(my.doc.field, true)]', $p->q());
+        $p = Predicates::at('my.doc.field', false);
+        $this->assertEquals('[:d = at(my.doc.field, false)]', $p->q());
+    }
 }