diff --git a/includes/helpers/helpers-ical.php b/includes/helpers/helpers-ical.php
index 3cb0ca1..e8feed3 100644
--- a/includes/helpers/helpers-ical.php
+++ b/includes/helpers/helpers-ical.php
@@ -75,6 +75,10 @@ function calendarp_ical_sync_events() {
 			$feed['type'] = $feeds[ $i ]['type'] = 'ical';
 		}
 
+		if ( isset( $feed['last_sync'] ) ) {
+			$feeds[ $i ]['prev_sync_time'] = $feed['last_sync']['time'];
+		}
+
 		$feeds[ $i ]['last_sync'] = array(
 			'time'   => current_time( 'timestamp' ),
 			'status' => 'incomplete',
@@ -158,7 +162,6 @@ function calendarp_ical_sync_events() {
 						$event_data['to'] = strtotime( $to[0]['data'] );
 					}
 				}
-
 				$events[] = $event_data;
 			}
 
diff --git a/includes/ical/class-calendar-plus-ical-sync.php b/includes/ical/class-calendar-plus-ical-sync.php
index 5e29589..68a83a8 100644
--- a/includes/ical/class-calendar-plus-ical-sync.php
+++ b/includes/ical/class-calendar-plus-ical-sync.php
@@ -36,6 +36,12 @@ class Calendar_Plus_iCal_Sync {
 	 */
 	protected $default_status;
 
+	/**
+	 * Time of previous synchronization to check if post was modified
+	 * @var int
+	 */
+	protected $prev_sync_time;
+
 	/**
 	 * Calendar_Plus_iCal_Sync constructor.
 	 *
@@ -47,14 +53,16 @@ public function __construct( $events, $args = [] ) {
 		$this->locations = calendarp_get_locations();
 
 		$args = wp_parse_args( $args, [
-			'author'   => 0,
-			'category' => 0,
-			'status'   => 'publish',
+			'author'         => 0,
+			'category'       => 0,
+			'status'         => 'publish',
+			'prev_sync_time' => time(),
 		] );
 
 		$this->event_author = $args['author'] ? $args['author'] : get_current_user_id();
 		$this->event_category = $args['category'];
 		$this->default_status = $args['status'];
+		$this->prev_sync_time = $args['prev_sync_time'];
 	}
 
 	/**
@@ -94,6 +102,7 @@ protected function sync_event( $event_data ) {
 			'last_updated' => '',
 			'categories'   => [],
 		] );
+		$event_data['hash'] = md5( serialize( $event_data ) );
 
 		if ( 'publish' === $event_data['post_status'] ) {
 			$event_data['post_status'] = $this->default_status;
@@ -115,7 +124,24 @@ protected function sync_event( $event_data ) {
 				return $event->ID;
 			}
 
-			if ( ! $event_data['last_updated'] || $event_data['last_updated'] === $event->get_meta( 'ical_last_updated' ) ) {
+			$event_post  = $event->get_post();
+			// Skip if there are no changes
+			if (
+				! empty( $event_data['last_updated'] ) &&
+				$event_data['last_updated'] === $event->get_meta( 'ical_last_updated' )
+			) {
+				return false;
+			}
+			// Skip if there are no changes
+			$old_event_hash = $event->get_meta( 'ical_hash' );
+			if ( $event_data['hash'] === $event->get_meta( 'ical_hash' ) ) {
+				return false;
+			}
+
+			if (
+				empty( $old_event_hash ) &&
+				$event_post->post_modified !== $event_post->post_date
+			) {
 				return false;
 			}
 
@@ -168,6 +194,8 @@ protected function sync_event( $event_data ) {
 			update_post_meta( $post_id, '_ical_last_updated', $event_data['last_updated'] );
 		}
 
+		update_post_meta( $post_id, '_ical_hash', $event_data['hash'] );
+
 		return $post_id;
 	}