How to change the default webmail client?

I’m a new mxroute customer, everything seems to works perfectly, however when I go to webmail.mydomain.com, the default webmail is RoundCube, and I would prefer to use Crossbox.
I found the following post that seems to address the question, however I feel that the answer is outdated and relate to an older system ? Thanks for your help !
How to Change Default Webmail Client Away from CrossBox?

Hello,

The post that you discovered actually addresses the cPanel based service which is no longer offered to new clients. As you mention that you are a newer client, I will make the assumptuon that it does not apply to you.

You can indeed, however make Crossbox your default webmail client by activating their branding feature. To do so you must create an email account for the user admin@ on your domain. With that account log in to Crossbox and you will have an 'Admin" menu available. Follow that and select “Branding” which will open into apage where you can rebrand Crossbox to be your own personal email client by uploading a logo and choosing a subdomain for it to be hosted on.

I have heard reports of it working fine on the subdomain ‘webmail’ though I have never personally used that specidic subdomain. Do keep in mind that if you choose the subdomain webmail you will lose access to the other webmail options as to complete this process you need to change the CNAME record to mail.mxlogin.com from 'yourserver.mxrouting.net` so at that point the subdomain will no longer point to the MXroute server.

Thanks, I’ll wait for the “official” documentation, I’m in no hurry.

Note that this is not a process we’ve fully vetted and documented, this is merely a feature that does exist and can be utilized ahead of us doing so. Officially the supported and documented method for a custom hostname webmail on MXroute is exclusive to roundcube. This abandons that documentation to take a different path altogether. I still do intend to document the process separately for crossbox, but it’s a low priority on my list.