diff --git a/.gitignore b/.gitignore
index 9ebe3aee..a8900649 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,3 +8,4 @@ clover.xml
 /.phpunit.result.cache
 /.idea
 /dev-scripts
+/*.code-workspace
diff --git a/src/Resource/BaseResource.php b/src/Resource/BaseResource.php
index 800b00d1..eb59ea01 100644
--- a/src/Resource/BaseResource.php
+++ b/src/Resource/BaseResource.php
@@ -14,7 +14,6 @@
 use Contentful\Core\Api\Link;
 use Contentful\Core\Resource\SystemPropertiesInterface;
 use Contentful\Management\Client;
-use function GuzzleHttp\json_encode as guzzle_json_encode;
 
 /**
  * BaseResource class.
@@ -64,7 +63,7 @@ public function asRequestBody()
 
         unset($body['sys']);
 
-        return guzzle_json_encode((object) $body, \JSON_UNESCAPED_UNICODE);
+        return \GuzzleHttp\Utils::jsonEncode((object) $body, JSON_UNESCAPED_UNICODE | JSON_INVALID_UTF8_SUBSTITUTE);
     }
 
     /**
diff --git a/src/Resource/DeliveryApiKey.php b/src/Resource/DeliveryApiKey.php
index 40085a24..42f0808d 100644
--- a/src/Resource/DeliveryApiKey.php
+++ b/src/Resource/DeliveryApiKey.php
@@ -15,7 +15,6 @@
 use Contentful\Management\Resource\Behavior\CreatableInterface;
 use Contentful\Management\Resource\Behavior\DeletableTrait;
 use Contentful\Management\Resource\Behavior\UpdatableTrait;
-use function GuzzleHttp\json_encode as guzzle_json_encode;
 
 /**
  * DeliveryApiKey class.
@@ -68,7 +67,7 @@ public function asRequestBody(): string
             unset($body['environments']);
         }
 
-        return guzzle_json_encode((object) $body, \JSON_UNESCAPED_UNICODE);
+        return \GuzzleHttp\Utils::jsonEncode((object) $body, JSON_UNESCAPED_UNICODE | JSON_INVALID_UTF8_SUBSTITUTE);
     }
 
     /**
diff --git a/src/Resource/Entry.php b/src/Resource/Entry.php
index e2520358..ae976e20 100644
--- a/src/Resource/Entry.php
+++ b/src/Resource/Entry.php
@@ -51,6 +51,11 @@ class Entry extends BaseResource implements EntryInterface, CreatableInterface
      */
     protected $fields = [];
 
+    /**
+     * @var array[]
+     */
+    protected $metadata = [];
+
     /**
      * Entry constructor.
      */
@@ -79,10 +84,16 @@ public function jsonSerialize(): array
             }
         }
 
-        return [
+        $entry = [
             'sys' => $this->sys,
             'fields' => (object) $fields,
         ];
+
+        if ($this->metadata) {
+            $entry['metadata'] = (object) $this->metadata;
+        }
+
+        return $entry;
     }
 
     /**
@@ -214,6 +225,73 @@ public function setField(string $name, string $locale, $value)
         return $this;
     }
 
+    /**
+     * @param string $name
+     * @return array|null
+     */
+    public function getMetadataValue(string $name)
+    {
+        return $this->metadata[$name] ?? null;
+    }
+
+    /**
+     * @return array
+     */
+    public function getMetadata(): array
+    {
+        return $this->metadata;
+    }
+
+    /**
+     * @param string $name
+     * @param mixed $value
+     * @return $this
+     */
+    public function setMetadataValue(string $name, $value)
+    {
+        $this->metadata[$name] = $value;
+
+        return $this;
+    }
+
+    /**
+     * @param string $tagId
+     * @return $this
+     */
+    public function addTag(string $tagId)
+    {
+        $tags = $this->getMetadataValue('tags') ?? [];
+
+        // Prevent attempting to set a duplicate tag
+
+        foreach ($tags as $tag) {
+            if ($tag['sys']['id'] === $tagId) {
+                return;
+            }
+        }
+
+        $tags[] = [
+            'sys' => [
+                'type' => 'Link',
+                'linkType' => 'Tag',
+                'id' => $tagId,
+            ],
+        ];
+
+        return $this->setMetadataValue('tags', $tags);
+    }
+
+    /**
+     * @param string $tagId
+     * @return $this
+     */
+    public function removeTag(string $tagId)
+    {
+        return $this->setMetadataValue('tags', array_values(array_filter($this->getMetadataValue('tags') ?? [], function (array $tag) use ($tagId) {
+            return $tag['sys']['id'] !== $tagId;
+        })));
+    }
+
     /**
      * Provides simple setX/getX capabilities,
      * without recurring to code generation.
diff --git a/src/Resource/Environment.php b/src/Resource/Environment.php
index 081acd4b..b382cb2b 100644
--- a/src/Resource/Environment.php
+++ b/src/Resource/Environment.php
@@ -16,7 +16,6 @@
 use Contentful\Management\Resource\Behavior\DeletableTrait;
 use Contentful\Management\Resource\Behavior\UpdatableTrait;
 use Contentful\Management\SystemProperties\Environment as SystemProperties;
-use function GuzzleHttp\json_encode as guzzle_json_encode;
 
 /**
  * Environment class.
@@ -85,7 +84,7 @@ public function asRequestBody(): string
 
         unset($body['sys']);
 
-        return guzzle_json_encode((object) $body, \JSON_UNESCAPED_UNICODE);
+        return \GuzzleHttp\Utils::jsonEncode((object) $body, JSON_UNESCAPED_UNICODE | JSON_INVALID_UTF8_SUBSTITUTE);
     }
 
     /**
diff --git a/src/Resource/Locale.php b/src/Resource/Locale.php
index bb242130..73214e8c 100644
--- a/src/Resource/Locale.php
+++ b/src/Resource/Locale.php
@@ -15,7 +15,6 @@
 use Contentful\Management\Resource\Behavior\DeletableTrait;
 use Contentful\Management\Resource\Behavior\UpdatableTrait;
 use Contentful\Management\SystemProperties\Locale as SystemProperties;
-use function GuzzleHttp\json_encode as guzzle_json_encode;
 
 /**
  * Locale class.
@@ -116,7 +115,7 @@ public function asRequestBody(): string
         // The property 'default' has to be omitted for the API to work.
         unset($body['default']);
 
-        return guzzle_json_encode((object) $body, \JSON_UNESCAPED_UNICODE);
+        return \GuzzleHttp\Utils::jsonEncode((object) $body, JSON_UNESCAPED_UNICODE | JSON_INVALID_UTF8_SUBSTITUTE);
     }
 
     /**
diff --git a/src/Resource/PersonalAccessToken.php b/src/Resource/PersonalAccessToken.php
index 7232619e..1a545e88 100644
--- a/src/Resource/PersonalAccessToken.php
+++ b/src/Resource/PersonalAccessToken.php
@@ -14,7 +14,6 @@
 use Contentful\Core\Api\DateTimeImmutable;
 use Contentful\Management\Resource\Behavior\CreatableInterface;
 use Contentful\Management\SystemProperties\PersonalAccessToken as SystemProperties;
-use function GuzzleHttp\json_encode as guzzle_json_encode;
 
 /**
  * PersonalAccessToken class.
@@ -94,7 +93,7 @@ public function asRequestBody(): string
         unset($body['token']);
         unset($body['revokedAt']);
 
-        return guzzle_json_encode((object) $body, \JSON_UNESCAPED_UNICODE);
+        return \GuzzleHttp\Utils::jsonEncode((object) $body, JSON_UNESCAPED_UNICODE | JSON_INVALID_UTF8_SUBSTITUTE);
     }
 
     /**
diff --git a/src/Resource/Space.php b/src/Resource/Space.php
index 9d06a79e..fbecc816 100644
--- a/src/Resource/Space.php
+++ b/src/Resource/Space.php
@@ -16,7 +16,6 @@
 use Contentful\Management\Resource\Behavior\DeletableTrait;
 use Contentful\Management\Resource\Behavior\UpdatableTrait;
 use Contentful\Management\SystemProperties\Space as SystemProperties;
-use function GuzzleHttp\json_encode as guzzle_json_encode;
 
 /**
  * Space class.
@@ -94,7 +93,7 @@ public function asRequestBody(): string
             $body['defaultLocale'] = $this->defaultLocale;
         }
 
-        return guzzle_json_encode((object) $body, \JSON_UNESCAPED_UNICODE);
+        return \GuzzleHttp\Utils::jsonEncode((object) $body, JSON_UNESCAPED_UNICODE | JSON_INVALID_UTF8_SUBSTITUTE);
     }
 
     /**