There are two ways to upgrade Boom Timeline to the Starter plan:
Option 1: From the Wix Editor (Settings Panel)
Open your website in the Wix Editor.
Double-click the Timeline widget to open the Settings panel.
Scroll to the bottom of the Settings panel and click the Upgrade button.
You will be taken to the Wix upgrade page for Timeline by BoomTech.
Choose your billing cycle — Monthly ($5.99/mo) or Yearly ($3.99/mo, save up to 33%).
Click Select on the Starter plan.
Choose your payment method and click Submit Purchase.
Option 2: From the Wix Dashboard
Log in to your Wix Dashboard.
Go to Apps > Manage Apps in the left sidebar.
Find Timeline in your list of installed apps.
Click the Upgrade button next to it.
Choose your billing cycle and complete the payment.
Your upgrade will take effect immediately and the 4-event limit will be removed. All events from your Wix Events will be displayed on the timeline.