I works with php 7.0 but I get this error when try to login when using 7.1:
Deprecated: Function mcrypt_module_open() is deprecated in /home/clients/3750c02f0a36c9f406774f5e0644fa4b/web/flarum/vendor/ircmaxell/random-lib/lib/RandomLib/AbstractMcryptMixer.php on line 75
Deprecated: Function mcrypt_enc_get_block_size() is deprecated in /home/clients/3750c02f0a36c9f406774f5e0644fa4b/web/flarum/vendor/ircmaxell/random-lib/lib/RandomLib/AbstractMcryptMixer.php on line 76
Deprecated: Function mcrypt_enc_get_iv_size() is deprecated in /home/clients/3750c02f0a36c9f406774f5e0644fa4b/web/flarum/vendor/ircmaxell/random-lib/lib/RandomLib/AbstractMcryptMixer.php on line 77
Deprecated: Function mcrypt_module_close() is deprecated in /home/clients/3750c02f0a36c9f406774f5e0644fa4b/web/flarum/vendor/ircmaxell/random-lib/lib/RandomLib/AbstractMcryptMixer.php on line 86
Fatal error: Uncaught RuntimeException: Output has been emitted previously; cannot emit response in /home/clients/3750c02f0a36c9f406774f5e0644fa4b/web/flarum/vendor/zendframework/zend-diactoros/src/Response/SapiEmitterTrait.php:41 Stack trace: #0 /home/clients/3750c02f0a36c9f406774f5e0644fa4b/web/flarum/vendor/zendframework/zend-diactoros/src/Response/SapiEmitter.php(30): Zend\Diactoros\Response\SapiEmitter->assertNoPreviousOutput() #1 /home/clients/3750c02f0a36c9f406774f5e0644fa4b/web/flarum/vendor/zendframework/zend-diactoros/src/Server.php(167): Zend\Diactoros\Response\SapiEmitter->emit(Object(Zend\Diactoros\Response\RedirectResponse)) #2 /home/clients/3750c02f0a36c9f406774f5e0644fa4b/web/flarum/vendor/flarum/core/src/Http/AbstractServer.php(36): Zend\Diactoros\Server->listen(Object(Zend\Stratigility\NoopFinalHandler)) #3 /home/clients/3750c02f0a36c9f406774f5e0644fa4b/web/flarum/index.php(16): Flarum\Http\AbstractServer->listen() #4 {main} thrown in /home/clients/3750c02f0a36c9f406774f5e0644fa4b/web/flarum/vendor/zendframework/zend-diactoros/src/Response/SapiEmitterTrait.php on line 41