Can't update bootstrap 4 to alpha 5, how to update?

Question

Yii

Problem 1
- Installation request for bower-asset/bootstrap 4.0.0-alpha.5 -> satisfiable by bower-asset/bootstrap[v4.0.0-alpha.5].
- Conclusion: remove bower-asset/tether v1.2.4
- yiisoft/yii2-bootstrap 2.1.x-dev requires bower-asset/tether 1.2.* -> satisfiable by bower-asset/tether[v1.2.4].
- yiisoft/yii2-bootstrap 2.1.x-dev requires bower-asset/tether 1.2.* -> satisfiable by bower-asset/tether[v1.2.4].
- Conclusion: don't install bower-asset/tether v1.2.4
- Installation request for yiisoft/yii2-bootstrap [email protected] -> satisfiable by yiisoft/yii2-bootstrap[2.1.x-dev].

composer.json content:

{
    "minimum-stability": "stable",
    "require": {
        "yiisoft/yii2": "dev-master",
        "yiisoft/yii2-bootstrap": "[email protected]",
        "bower-asset/bootstrap": "4.0.0-alpha.5",
        "bower-asset/font-awesome": "4.*",
        "bower-asset/jquery": "2.*",
        "bower-asset/highlightjs": "9.*",
        "bower-asset/js-cookie": "2.*",
        "yiisoft/yii2-authclient": "2.*",
        "yiisoft/yii2-swiftmailer": "2.*"
    },
    "require-dev": {
        "yiisoft/yii2-codeception": "*",
        "yiisoft/yii2-debug": "*",
        "yiisoft/yii2-gii": "*",
        "yiisoft/yii2-faker": "*"
    },
    "extra": {
        "asset-installer-paths": {
            "npm-asset-library": "vendor/npm",
            "bower-asset-library": "vendor/bower"
        }
    }
}

If you specify "bower-asset/bootstrap": "[email protected]", then it updates to alpha 4 at most
. Need version version alpha 5, they added a class for vertical-align...

Answer 1

А альфа-5 уже появилась в пакетах/репозиториях, с которых Вы его обновить пытаетесь? Подозреваю, что пока ещё нет.
Думаю, решить проблему можно путём замены изменившихся файлов "руками".
Ну, или подключением 5-ой версии с CDN'а, вместо использования оного локально.

Answer 2

From StackOverflow:

$video_url = https://www.youtube.com/oembed?format=json&url=http://www.youtube.com/watch?v=VideoId

$video_url = @file_get_contents($video_url);
if($video_url) {
    echo('video exists');
} else {
    echo('video does not exists');
};

Answer 3

If you don’t feel like working with the youtube api at all, then you can make a small “hack” to check the video thumbnail. The "hack" is rather mediocre, if suddenly the size of the stub or something changes on youtube, then you will need to edit the code again.

var img = new Image();  
img.onload = function(){
    if(img.naturalWidth == 120) //120 - ширина заглушки миниатюры видео
    alert('video not working');
};
img.src = 'https://img.youtube.com/vi/HQpB2PZnZzo1/mqdefault.jpg';  //подгружаем миниатюру видео большого размера

I do not recommend using.