There are a number of websites around providing information about Swyx respectively SwyxWare.
The most important website is of course www.swyx.com itself. Beside that this site, www.swyx-forum.com, became a very informative and usefull resource as well.
So there are at least two different websites with lots of information, tools and help somewhere "hidden" deeply on a sub-sub-sub page.
Not an easy task to find all relvant information to stay up to date manually !
Luckily both sites offer email newsletters, email notifications and rss feeds to make this job as automated and easy as possible.
Swyx
Swyx offers two different newsletters. The company newsletter and the support newsletter. The first one provides common information on new versions, sales and marketing news a.s.o.. The second one informs you about every new of modifed article within the support knowledgebase.
Use the following links to subscribe to the newsletters:
Swyx Newsletter
http://www.swyx.com/uk/service/newsletter.html
Swyx Support Newsletter
http://www.swyx.com/uk/support/newsletter.html
The support newsletter can be configured to be sent daily, weekly or monthly if there is something to tell within this timeframe. I suggest using the daily interval.
If you want to get the emails in german language just replace "uk" by "de" in the above links.
If you have a Swyx Partner Net Account you should subscribe to the support newsletter from there (Menu: Support - Newsletter) in order to get all the partner relevant informations sent as well !
Swyx Forum
Swyx Forum provides automated email notifications. There are two different types of these notifications: the Forum Notifications and the "Keep me up-to-date" feature.
Forum Notifications
You can use the Forum Notifications as a kind of mailing list to get all posts within the forum sent by email to you, or just use it to get notifications if someone answered your question witihn the forum. You configure the notifications within your personal forum settings (My Settings button in the forum toolbar). To use the notification as a mailing just tick all the forums in the list.
"Keep me up-to-date"
Beside the forums this page has a number of other also informative and important sections, like the blogs, the downloads, the News and the Wiki. If you don't want to miss any new items in here just configure your personal "Keep me up-to-date". You'll find it after begin logged in to Swyx Forum at the left bottom of the state page. Just select what you want to know and click "Update". Read more about this feature here.
RSS Feeds
Swyx and Swyx Forum also provide a number of different RSS feeds. So where ever you find the rss icon 
just click on it to subscribe to that feed using your prefered feed program.
My personal suggestion to you:
Subscribe to the Swyx Newsletter, the Swyx Support Newsletter, the Forum Notifications and some of the "Keep me up-to-date" settings: Blogs, Downloads, News, Wiki. The both "Swyx" checkboxes are not needed as the two Swyx Newsletter will provide this information as well. All this will cover *all* available content of the rss feeds as well !
So, following this suggestion you won't miss any relevant information anymore 