wordpress maintenance error

Why it is important to update to the latest version of WordPress? how can I update my website to 5.4.2 version of WordPress? Earlier I tried updating my WordPress site and add/deleted some plugins but it caused malfunction to my site speed and navigation. Should I hire a WordPress maintenance...

While updating few plugins in wordpress, the wordpress automatically puts the website in Maintenance mode. During the update process if there is time out or sever response is too slow then that is the time you get the following error: Briefly unavailable for scheduled maintenance. Check back in...