• Clean up arg orders of handlers that have had added args pushed at the end (after bubbling etc), maybe group them in an $options array or parameter objects? Needs RFC. Check Add fluent setters for parameters in the slack handler #801 too about fluent setters
• add scalar hints and return type hints where relevant ("only" handlers left to go through)
• figure out how to handle network timeouts globally somehow, see Allow custom connection_timeout to LogEntries handler #733
• Add a close() method on the Logger to close all its handlers? What about resetting FingersCrossedHandler?
• Define which php version should be supported (=> 7.1)
• Add a timezone arg to Logger instead of the static timezone?
• Turn static::getLevelName into static::
• Set Monolog\Logger::API = 2 to allow users to adjust
• Remove non PSR-3 methods to add record
• Remove processor/formatter setters and getters from the HandlerInterface
• Remove logstash V0 support or at least make V1 default
• Remove legacy GELF handler support, c.f. GELF: Allow for both the legacy and the updated official library #326
• Remove datetime TODO in loggly handler
• Move Monolog\TestCase to src/, see Create PEAR System_Daemon handler #356 (comment)
• Split handlers w/ dependencies into packages i.e. http://php-and-symfony.matthiasnoback.nl/2014/04/theres-no-such-thing-as-an-optional-dependency/
• Change Logger constants to have RFC values (https://github.com/php-fig/log/issues/8)
• Remove substr TODO in AmqpHandler
• Remove default handler ($this->pushHandler(new StreamHandler('php://stderr', static::DEBUG));) from Monolog\Logger
• Consider adding a public method (send or write or so) on handlers to make reusing them out of monolog easier, c.f. f3b61cf#commitcomment-8237858
• Consider using MongoDBFormatter as default in MongoDBHandler
• Drop support for outdated mongo exts in MongoDBHandler
• Remove BC __get() in SwiftMailerHandler
• Update HipChat to API v2 using 01549ec and room_id and from in buildContent (+ nickname everywhere) should be removed. See if we can't detect the token format and warn users using a v1 token.
• Check all PHP_VERSION and version_compare checks for relevance
• LineFormatter when showing stack traces should show new lines on new lines, and not the exception as part of the context that gets inlined into json => How to log multi line logs to stdout #752
• Consider removing useless PHP docs if the scalar + return type hints give enough info
• Disable microseconds timestamps by default?

php7 ideas:

• treat Error-class exceptions in a special way as they are replacing E_COMPILE_ERROR and such from defaultErrorLevelMap
• possibly remove ErrorHandler::registerFatalHandler if this is not needed anymore
• enable strict mode everywhere?

those items have been abandoned