Locate the listing for the certificate. Tap the link or the certificate option shown on the page.

Older Apple operating systems contain outdated root certificate stores. Over time, global certificate authorities expire, change their encryption standards, or require Server Name Identification (SNI), which legacy versions of Safari and Cydia cannot parse natively. The Let’s Encrypt Expiration Issue

The most critical asset hosted on the site is the updated certificate profile. By installing this profile, users manually teach their legacy iOS devices to trust modern web servers again. This single installation instantly restores functionality to Safari and various web-dependent jailbreak tweaks. Key Tweaks Hosted on the Repository

Messages stating Safari "could not establish a secure connection" to popular sites.