Modernise Webmail Gui
In order to be able to sell Mdaemon to prospective new clients I do need to wow them a bit with the GUI as this is the first thing that most end clients see and care about. They don't care about spam filtering, back end administration etc which are the things that I care about for Mdaemon.
I don't think that you need to make huge changes to your CSS coding. In fact, most of the changes I am suggesting would probably be quite minor.
Replace the flag, category, select icons etc with more modern looking icons. A lot of the icons within webmail are a bit basic looking. I am not sure if it's the colour, size or the icons themselves etc as I am not a graphic designer. I just can see that it looks a bit dated in a way.
Most email programs are moving to a double or triple line view for each message, where you can see a snippet of the email message as well. For some reason that I don't know, it does dramatically change the look of the webmail program for the better as well if the rows are much higher than standard one line rows. That spacing just seems to display better for some reason. It also helps to show emails that have been categorised better if you have a line down the length of the row highlighting the category colour instead of a small square like you currently do.
Hover over appointments in calendar to have a bubble display of the whole event. You already have this, but it's a very basic looking html bubble compared to say Em client or Outlook. The calendar view just looks very basic overall.
I also think the issue may be the default font used in Webmail. Some fonts just look more modern than other fonts. But it may be because there is just too much grey everywhere? I am not sure, but the email window look is a bit bland.
Below, is an example of what I am suggesting. However I am not indicating that you should implement this exact design as your developers will have lots of ideas of their own no doubt.
But a picture does better illustrate where I think the gui design should be going. You have already done this to a very large extent with the MDIM app within the webmail. I would imagine that you just need to port the CSS coding from the MDIM within webmail to the actual Webmail itself?
Thanks Robert