zackdesign

This plugin is deprecated and should not be used for new installations.
PayPal API Subscriptions was built in 2008 using the PayPal NVP (Name-Value Pair) API v52.0, which PayPal has since discontinued in favour of their REST APIs. The plugin also directly handles raw credit card numbers on your server, which creates PCI compliance obligations that most WordPress sites cannot meet.
Recommended alternatives:
<ul>
<li><a href="https://woocommerce.com/products/woocommerce-paypal-payments/" rel="nofollow ugc">WooCommerce + PayPal Payments</a> — modern PayPal integration with Smart Buttons (card data never touches your server)</li>
<li><a href="https://www.memberpress.com/" rel="nofollow ugc">MemberPress</a> — full membership/subscription management with PayPal and Stripe</li>
<li><a href="https://www.paidmembershipspro.com/" rel="nofollow ugc">Paid Memberships Pro</a> — free membership plugin with PayPal support</li>
</ul>
What happens in v1.2.0:
<ul>
<li>Existing <code>[ppsa]</code> shortcodes display a retirement message instead of subscription buttons</li>
<li>An admin notice reminds you to migrate</li>
<li>All PayPal API code, the credit card form, and bundled jQuery have been removed</li>
</ul>

PayPal API Subscriptions

DEPRECATED — This plugin uses the discontinued PayPal NVP API and handles raw credit card data. Please switch to a modern alternative.

tamlyn

As a theme developer, you want to have WP_DEBUG enabled but you’re not interested in the deprecated warnings created by other plugins. Use this plugin to disable these messages while still displaying other errors, warnings and notices.
<a href="http://outlandishideas.co.uk/blog/2012/06/hide-deprecated-errors-in-wordpress/" rel="nofollow ugc">Plugin by Outlandish Ideas</a>

Disable Deprecated Warnings

Prevents plugins from showing deprecated errors in the WordPress admin.

PayPal API Subscriptions vs Disable Deprecated Warnings