Migration Failed: Database Error

I am getting error when I try migration:

Warnings:
You are importing from a newer version of WordPress (4.8.3) into an older one (4.7.7). There are no guarantees that WordPress can handle this.
The site in this backup was running on a webserver with version 7.0 of PHP. This is significantly newer than the server which you are now restoring onto (version 5.6.21). You should only proceed if you cannot update the current server and are confident (or willing to risk) that your plugins/themes/etc. are compatible with the older PHP version. Any support requests to do with PHP should be raised with your web hosting company.

The database server that this WordPress site is running on doesn’t support the character set (utf8mb4) which you are trying to import. You can choose another suitable character set instead and continue with the restoration at your own risk. Go here for more information. Go here for more information.
The database server that this WordPress site is running on doesn’t support the collation (utf8mb4_unicode_ci) used in the database which you are trying to import. You can choose another suitable collation instead and continue with the restoration (at your own risk).

Errors:
Error: The database backup uses MySQL features not available in the old MySQL version (5.1.63) that this site is running on. You must upgrade MySQL to be able to use this database.

Thanks