diff --git a/mailstream/mailstream.php b/mailstream/mailstream.php
index a58dfc1c..d6d880f1 100644
--- a/mailstream/mailstream.php
+++ b/mailstream/mailstream.php
@@ -14,6 +14,7 @@ use Friendica\Core\Logger;
 use Friendica\Core\PConfig;
 use Friendica\Core\Renderer;
 use Friendica\Database\DBA;
+use Friendica\Protocol\Activity;
 use Friendica\Util\Network;
 use Friendica\Model\Item;
 
@@ -122,7 +123,7 @@ function mailstream_post_hook(&$a, &$item) {
 		return;
 	}
 	if (PConfig::get($item['uid'], 'mailstream', 'nolikes')) {
-		if ($item['verb'] == ACTIVITY_LIKE) {
+		if ($item['verb'] == Activity::LIKE) {
 			Logger::debug('mailstream: like item ' . $item['id']);
 			return;
 		}
diff --git a/pumpio/pumpio.php b/pumpio/pumpio.php
index 537bf280..e8b740c2 100644
--- a/pumpio/pumpio.php
+++ b/pumpio/pumpio.php
@@ -21,6 +21,8 @@ use Friendica\Model\Contact;
 use Friendica\Model\Group;
 use Friendica\Model\Item;
 use Friendica\Model\User;
+use Friendica\Protocol\Activity;
+use Friendica\Protocol\ActivityNamespace;
 use Friendica\Util\ConfigFileLoader;
 use Friendica\Util\DateTimeFormat;
 use Friendica\Util\Network;
@@ -480,7 +482,7 @@ function pumpio_send(App $a, array &$b)
 		}
 	}
 
-	if ($b['verb'] == ACTIVITY_LIKE) {
+	if ($b['verb'] == Activity::LIKE) {
 		if ($b['deleted']) {
 			pumpio_action($a, $b["uid"], $b["thr-parent"], "unlike");
 		} else {
@@ -489,15 +491,15 @@ function pumpio_send(App $a, array &$b)
 		return;
 	}
 
-	if ($b['verb'] == ACTIVITY_DISLIKE) {
+	if ($b['verb'] == Activity::DISLIKE) {
 		return;
 	}
 
-	if (($b['verb'] == ACTIVITY_POST) && ($b['created'] !== $b['edited']) && !$b['deleted']) {
+	if (($b['verb'] == Activity::POST) && ($b['created'] !== $b['edited']) && !$b['deleted']) {
 		pumpio_action($a, $b["uid"], $b["uri"], "update", $b["body"]);
 	}
 
-	if (($b['verb'] == ACTIVITY_POST) && $b['deleted']) {
+	if (($b['verb'] == Activity::POST) && $b['deleted']) {
 		pumpio_action($a, $b["uid"], $b["uri"], "delete");
 	}
 
@@ -560,8 +562,8 @@ function pumpio_send(App $a, array &$b)
 			$inReplyTo = ["id" => $orig_post["uri"],
 				"objectType" => "note"];
 
-			if (($orig_post["object-type"] != "") && (strstr($orig_post["object-type"], NAMESPACE_ACTIVITY_SCHEMA))) {
-				$inReplyTo["objectType"] = str_replace(NAMESPACE_ACTIVITY_SCHEMA, '', $orig_post["object-type"]);
+			if (($orig_post["object-type"] != "") && (strstr($orig_post["object-type"], ActivityNamespace::ACTIVITY_SCHEMA))) {
+				$inReplyTo["objectType"] = str_replace(ActivityNamespace::ACTIVITY_SCHEMA, '', $orig_post["object-type"]);
 			}
 
 			$params["object"] = [
@@ -636,8 +638,8 @@ function pumpio_action(App $a, $uid, $uri, $action, $content = "")
 		$uri = $orig_post["uri"];
 	}
 
-	if (($orig_post["object-type"] != "") && (strstr($orig_post["object-type"], NAMESPACE_ACTIVITY_SCHEMA))) {
-		$objectType = str_replace(NAMESPACE_ACTIVITY_SCHEMA, '', $orig_post["object-type"]);
+	if (($orig_post["object-type"] != "") && (strstr($orig_post["object-type"], ActivityNamespace::ACTIVITY_SCHEMA))) {
+		$objectType = str_replace(ActivityNamespace::ACTIVITY_SCHEMA, '', $orig_post["object-type"]);
 	} elseif (strstr($uri, "/api/comment/")) {
 		$objectType = "comment";
 	} elseif (strstr($uri, "/api/note/")) {
@@ -914,7 +916,7 @@ function pumpio_dounlike(App $a, $uid, $self, $post, $own_id)
 		}
 	}
 
-	Item::delete(['verb' => ACTIVITY_LIKE, 'uid' => $uid, 'contact-id' => $contactid, 'thr-parent' => $orig_post['uri']]);
+	Item::delete(['verb' => Activity::LIKE, 'uid' => $uid, 'contact-id' => $contactid, 'thr-parent' => $orig_post['uri']]);
 
 	if (DBA::isResult($r)) {
 		Logger::log("pumpio_dounlike: unliked existing like. User ".$own_id." ".$uid." Contact: ".$contactid." Url ".$orig_post['uri']);
@@ -969,7 +971,7 @@ function pumpio_dolike(App $a, $uid, $self, $post, $own_id, $threadcompletion =
 		}
 	}
 
-	$condition = ['verb' => ACTIVITY_LIKE, 'uid' => $uid, 'contact-id' => $contactid, 'thr-parent' => $orig_post['uri']];
+	$condition = ['verb' => Activity::LIKE, 'uid' => $uid, 'contact-id' => $contactid, 'thr-parent' => $orig_post['uri']];
 	if (Item::exists($condition)) {
 		Logger::log("pumpio_dolike: found existing like. User ".$own_id." ".$uid." Contact: ".$contactid." Url ".$orig_post['uri']);
 		return;
@@ -977,7 +979,7 @@ function pumpio_dolike(App $a, $uid, $self, $post, $own_id, $threadcompletion =
 
 	$likedata = [];
 	$likedata['parent'] = $orig_post['id'];
-	$likedata['verb'] = ACTIVITY_LIKE;
+	$likedata['verb'] = Activity::LIKE;
 	$likedata['gravity'] = GRAVITY_ACTIVITY;
 	$likedata['uid'] = $uid;
 	$likedata['wall'] = 0;
@@ -996,11 +998,11 @@ function pumpio_dolike(App $a, $uid, $self, $post, $own_id, $threadcompletion =
 	$objauthor =  '[url=' . $orig_post['author-link'] . ']' . $orig_post['author-name'] . '[/url]';
 	$post_type = L10n::t('status');
 	$plink = '[url=' . $orig_post['plink'] . ']' . $post_type . '[/url]';
-	$likedata['object-type'] = ACTIVITY_OBJ_NOTE;
+	$likedata['object-type'] = Activity\ObjectType::NOTE;
 
 	$likedata['body'] = L10n::t('%1$s likes %2$s\'s %3$s', $author, $objauthor, $plink);
 
-	$likedata['object'] = '<object><type>' . ACTIVITY_OBJ_NOTE . '</type><local>1</local>' .
+	$likedata['object'] = '<object><type>' . Activity\ObjectType::NOTE . '</type><local>1</local>' .
 		'<id>' . $orig_post['uri'] . '</id><link>' . XML::escape('<link rel="alternate" type="text/html" href="' . XML::escape($orig_post['plink']) . '" />') . '</link><title>' . $orig_post['title'] . '</title><content>' . $orig_post['body'] . '</content></object>';
 
 	$ret = Item::insert($likedata);
@@ -1147,7 +1149,7 @@ function pumpio_dopost(App $a, $client, $uid, $self, $post, $own_id, $threadcomp
 	$postarray['uid'] = $uid;
 	$postarray['wall'] = 0;
 	$postarray['uri'] = $post->object->id;
-	$postarray['object-type'] = NAMESPACE_ACTIVITY_SCHEMA.strtolower($post->object->objectType);
+	$postarray['object-type'] = ActivityNamespace::ACTIVITY_SCHEMA . strtolower($post->object->objectType);
 
 	if ($post->object->objectType != "comment") {
 		$contact_id = pumpio_get_contact($uid, $post->actor);
@@ -1230,7 +1232,7 @@ function pumpio_dopost(App $a, $client, $uid, $self, $post, $own_id, $threadcomp
 	}
 
 	$postarray['contact-id'] = $contact_id;
-	$postarray['verb'] = ACTIVITY_POST;
+	$postarray['verb'] = Activity::POST;
 	$postarray['owner-name'] = $post->actor->displayName;
 	$postarray['owner-link'] = $post->actor->url;
 	$postarray['author-name'] = $postarray['owner-name'];
diff --git a/statusnet/statusnet.php b/statusnet/statusnet.php
index ed7b87d8..fee8fd82 100644
--- a/statusnet/statusnet.php
+++ b/statusnet/statusnet.php
@@ -36,6 +36,7 @@
 define('STATUSNET_DEFAULT_POLL_INTERVAL', 5); // given in minutes
 
 require_once __DIR__ . DIRECTORY_SEPARATOR . 'library' . DIRECTORY_SEPARATOR . 'statusnetoauth.php';
+
 use CodebirdSN\CodebirdSN;
 use Friendica\App;
 use Friendica\Content\OEmbed;
@@ -48,7 +49,6 @@ use Friendica\Core\Logger;
 use Friendica\Core\PConfig;
 use Friendica\Core\Protocol;
 use Friendica\Core\Renderer;
-use Friendica\Core\System;
 use Friendica\Database\DBA;
 use Friendica\Model\Contact;
 use Friendica\Model\Group;
@@ -56,6 +56,7 @@ use Friendica\Model\Item;
 use Friendica\Model\ItemContent;
 use Friendica\Model\Photo;
 use Friendica\Model\User;
+use Friendica\Protocol\Activity;
 use Friendica\Util\DateTimeFormat;
 use Friendica\Util\Network;
 use Friendica\Util\Strings;
@@ -550,11 +551,11 @@ function statusnet_post_hook(App $a, &$b)
 		}
 	}
 
-	if (($b['verb'] == ACTIVITY_POST) && $b['deleted']) {
+	if (($b['verb'] == Activity::POST) && $b['deleted']) {
 		statusnet_action($a, $b["uid"], substr($orig_post["uri"], $hostlength), "delete");
 	}
 
-	if ($b['verb'] == ACTIVITY_LIKE) {
+	if ($b['verb'] == Activity::LIKE) {
 		Logger::log("statusnet_post_hook: parameter 2 " . substr($b["thr-parent"], $hostlength), Logger::DEBUG);
 		if ($b['deleted'])
 			statusnet_action($a, $b["uid"], substr($b["thr-parent"], $hostlength), "unlike");
@@ -1139,11 +1140,11 @@ function statusnet_createpost(App $a, $uid, $post, $self, $create_user, $only_ex
 			$postarray['thr-parent'] = $item['uri'];
 			$postarray['parent-uri'] = $item['parent-uri'];
 			$postarray['parent'] = $item['parent'];
-			$postarray['object-type'] = ACTIVITY_OBJ_COMMENT;
+			$postarray['object-type'] = Activity\ObjectType::COMMENT;
 		} else {
 			$postarray['thr-parent'] = $postarray['uri'];
 			$postarray['parent-uri'] = $postarray['uri'];
-			$postarray['object-type'] = ACTIVITY_OBJ_NOTE;
+			$postarray['object-type'] = Activity\ObjectType::NOTE;
 		}
 
 		// Is it me?
@@ -1167,7 +1168,7 @@ function statusnet_createpost(App $a, $uid, $post, $self, $create_user, $only_ex
 		$create_user = false;
 	} else {
 		$postarray['parent-uri'] = $postarray['uri'];
-		$postarray['object-type'] = ACTIVITY_OBJ_NOTE;
+		$postarray['object-type'] = Activity\ObjectType::NOTE;
 	}
 
 	if ($contactid == 0) {
@@ -1184,7 +1185,7 @@ function statusnet_createpost(App $a, $uid, $post, $self, $create_user, $only_ex
 
 	$postarray['contact-id'] = $contactid;
 
-	$postarray['verb'] = ACTIVITY_POST;
+	$postarray['verb'] = Activity::POST;
 
 	$postarray['author-name'] = $content->user->name;
 	$postarray['author-link'] = $content->user->statusnet_profile_url;
diff --git a/twitter/twitter.php b/twitter/twitter.php
index a43e8358..11f21a89 100644
--- a/twitter/twitter.php
+++ b/twitter/twitter.php
@@ -85,6 +85,7 @@ use Friendica\Model\Item;
 use Friendica\Model\ItemContent;
 use Friendica\Model\User;
 use Friendica\Object\Image;
+use Friendica\Protocol\Activity;
 use Friendica\Util\ConfigFileLoader;
 use Friendica\Util\DateTimeFormat;
 use Friendica\Util\Network;
@@ -556,11 +557,11 @@ function twitter_post_hook(App $a, array &$b)
 		}
 	}
 
-	if (($b['verb'] == ACTIVITY_POST) && $b['deleted']) {
+	if (($b['verb'] == Activity::POST) && $b['deleted']) {
 		twitter_action($a, $b["uid"], substr($orig_post["uri"], 9), "delete");
 	}
 
-	if ($b['verb'] == ACTIVITY_LIKE) {
+	if ($b['verb'] == Activity::LIKE) {
 		Logger::log("twitter_post_hook: parameter 2 " . substr($b["thr-parent"], 9), Logger::DEBUG);
 		if ($b['deleted']) {
 			twitter_action($a, $b["uid"], substr($b["thr-parent"], 9), "unlike");
@@ -1340,7 +1341,7 @@ function twitter_media_entities($post, array &$postarray)
 					$media[$medium->url] .= "\n[img]" . $medium->media_url_https . '[/img]';
 				}
 
-				$postarray['object-type'] = ACTIVITY_OBJ_IMAGE;
+				$postarray['object-type'] = Activity\ObjectType::IMAGE;
 				break;
 			case 'video':
 			case 'animated_gif':
@@ -1351,7 +1352,7 @@ function twitter_media_entities($post, array &$postarray)
 					$media[$medium->url] .= "\n[img]" . $medium->media_url_https . '[/img]';
 				}
 
-				$postarray['object-type'] = ACTIVITY_OBJ_VIDEO;
+				$postarray['object-type'] = Activity\ObjectType::VIDEO;
 				if (is_array($medium->video_info->variants)) {
 					$bitrate = 0;
 					// We take the video with the highest bitrate
@@ -1408,11 +1409,11 @@ function twitter_createpost(App $a, $uid, $post, array $self, $create_user, $onl
 			$postarray['thr-parent'] = $parent_item['uri'];
 			$postarray['parent-uri'] = $parent_item['parent-uri'];
 			$postarray['parent'] = $parent_item['parent'];
-			$postarray['object-type'] = ACTIVITY_OBJ_COMMENT;
+			$postarray['object-type'] = Activity\ObjectType::COMMENT;
 		} else {
 			$postarray['thr-parent'] = $postarray['uri'];
 			$postarray['parent-uri'] = $postarray['uri'];
-			$postarray['object-type'] = ACTIVITY_OBJ_NOTE;
+			$postarray['object-type'] = Activity\ObjectType::NOTE;
 		}
 
 		// Is it me?
@@ -1437,7 +1438,7 @@ function twitter_createpost(App $a, $uid, $post, array $self, $create_user, $onl
 		$create_user = false;
 	} else {
 		$postarray['parent-uri'] = $postarray['uri'];
-		$postarray['object-type'] = ACTIVITY_OBJ_NOTE;
+		$postarray['object-type'] = Activity\ObjectType::NOTE;
 	}
 
 	if ($contactid == 0) {
@@ -1457,7 +1458,7 @@ function twitter_createpost(App $a, $uid, $post, array $self, $create_user, $onl
 
 	$postarray['contact-id'] = $contactid;
 
-	$postarray['verb'] = ACTIVITY_POST;
+	$postarray['verb'] = Activity::POST;
 	$postarray['author-name'] = $postarray['owner-name'];
 	$postarray['author-link'] = $postarray['owner-link'];
 	$postarray['author-avatar'] = $postarray['owner-avatar'];
@@ -1480,7 +1481,7 @@ function twitter_createpost(App $a, $uid, $post, array $self, $create_user, $onl
 
 	// When the post contains links then use the correct object type
 	if (count($post->entities->urls) > 0) {
-		$postarray['object-type'] = ACTIVITY_OBJ_BOOKMARK;
+		$postarray['object-type'] = Activity\ObjectType::BOOKMARK;
 	}
 
 	// Search for media links
@@ -1518,9 +1519,9 @@ function twitter_createpost(App $a, $uid, $post, array $self, $create_user, $onl
 			Item::insert($retweet);
 
 			// CHange the other post into a reshare activity
-			$postarray['verb'] = ACTIVITY2_ANNOUNCE;
+			$postarray['verb'] = Activity::ANNOUNCE;
 			$postarray['gravity'] = GRAVITY_ACTIVITY;
-			$postarray['object-type'] = ACTIVITY_OBJ_NOTE;
+			$postarray['object-type'] = Activity\ObjectType::NOTE;
 
 			$postarray['thr-parent'] = $retweet['uri'];
 			$postarray['parent-uri'] = $retweet['uri'];