This change modifies the regular expression in ContentType::fromString() to allow parameters to contain the equals (=) character, and be optionally enclosed in double quotes. For example the following header is perfectly valid, but does not get currently parsed by ContentType: Content-type: text/plain; charset="us-ascii" Whilst allowing the parameter to be enclosed in double quotes, it should not be included in the value itself, so these are outside the capture group in the regular expression. This change should resolve issue #7076.
`null` will be a reserved keyword in PHP 7. This patch renames the `Null` mail transport to `InMemory`, and updates the factory to return an `InMemory` instance whenever `null` is retrieved. A future patch will re-add the `Null` transport with an `E_USER_DEPRECATION` notice.