Synchronization from Petal to an external calendar is possible with:

To synchronize your calendar:

1. Go to the Calendar section.

2. Click on My calendar.

3. Click on the Share your Calendar button at the top right of your screen.

4. Choose the desired external calendar and follow the procedure.

Apple Calendar

We have created a document that explains the configuration procedure step by step. Here is the link to the article:

Google Agenda