The first version of the rules for FSG2019 is now published. While overall no substantial changes have been applied, a lot of detailed work has been done to clarify and simplify the document.
https://www.formulastudent.de/fsg/rules/ 

If you find errors or inconsistencies in the document or you have a remark how to improve the document, use the Rules Feedback Tool, which is open now for one week. This is to improve the document for everyone. There you can also see all feedback from other teams. We will collect your feedback until Wednesday, 2018-09-26 13:00 CEST, and then publish the final version of the rules document, including your feedback, on Monday, 2018-10-01. 
https://www.formulastudent.de/fsg/rules/feedback/ 

If you have a question regarding a rule, e.g. if a special design solution is still compliant, use the Rules Questions Tool, which is open all year. This is to clarify your rules questions.
https://www.formulastudent.de/fsg/rules/questions/