Starting on 01 January 2007, all new code that is suggested for inclusion into PEAR must be E_STRICT-compatible. This means that it must not produce any warnings or errors when PHP's error reporting level is set to E_ALL | E_STRICT.
The development of existing packages that are not E_STRICT-compatible can continue as usual. If however a new major version of the package is released, this major version must then be E_STRICT-compatible.
More details on this part of the Coding Standards can be found in the corresponding RFC.