Hi,
I use Welcomme inn theme and contact form new version,and the theme developers gave this response to the problem:
I was trying to turn off any jQuery which is working with datepicker from our theme, but I found next: the problem for datepicker in Contact Form 7 is not coming from our theme but from latest WordPress version. This is said even by you in the top of this topic. I did not pay attention to this in the beginning, but now it is clear that the issue is created by not full compatibility of Contact Form 7 with WordPress 3.8. I can advice you to contact plugin’s authors and describe them this situation and see what they will reply about this.
This site https://relax-kucko.hu/teszt-bejelentkezes
Thanks
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