PHP 7 - Compatibility Check

My development team is looking to move our sites to a new server that runs on PHP 7. I was wondering what the reason is for using deprecated functions and I wanted to know if this will be updated.

Here are the errors:
FILE: /home/globaleducation/public_html/wp-content/plugins/wpmudev-updates/template/support-system.php
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FOUND 1 ERROR AND 4 WARNINGS AFFECTING 5 LINES
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77 | ERROR | Extension 'mysql_' is deprecated since PHP 5.5 and removed since PHP 7.0 - use mysqli instead.
313 | WARNING | Function name "__render_list" is discouraged; PHP has reserved all method names with a double underscore prefix for future use
334 | WARNING | Function name "__error_reporting" is discouraged; PHP has reserved all method names with a double underscore prefix for future use
376 | WARNING | Function name "__value_format" is discouraged; PHP has reserved all method names with a double underscore prefix for future use
390 | WARNING | Function name "__const_format" is discouraged; PHP has reserved all method names with a double underscore prefix for future use
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