I have moved this blog to my own server at www.rene-grothmann.de. I did this mainly because I can edit the CSS here. Strato lets me install a WordPress blog easily, and then I simply installed the Ari theme and activated it. Now I was able to do some finetuning to the CSS, since I do not like some of the large spacings and some fonts. For the Latex formulas I installed the Jetpack plugin. For some reason, it connects with my old WordPress account.
Moving from WordPress was easy with export and import, until I discovered that Latex formulas lost the reverse backslash \. I had to go through the posts manually and restore everything. Someone at the WordPress developing community ought to fix this.
I will continue blogging here in German and in English.