XF 2.3 ErrorException: Fatal Error: Declaration of Symfony\Component\Cache\CacheItem::get() must be compatible with Psr\Cache\CacheItemInterface::get(): mixe

[USY]

I recently updated to XF 2.3.6, I get this error:


When I call https://www.mydomain.com/help/bb-codes/ I get

 

[philmckrackon]

It's the addon Symfony error as shown in the declaration Error message. Not XF.

 

[USY]

It's the addon Symfony error as shown in the declaration Error message. Not XF.

Which addon and how to solve ?