idontknowhowtocode on "Fatal Error - Cant Login to admin. Cant do anything..."

Hello all,

I am new to wordpress and would be very grateful indeed for any advice on my problem.

When I enter my site name or admin login address I am greeted by this message:

Fatal error: Call to undefined function get_custom_logo() in /homepages/30/d186231185/htdocs/clickandbuilds/sonicegg/wp-content/themes/illdy/inc/back-compatible.php on line 7

I cant do anything it seems. Site is down, Cant change settings in admin because i cant login etc. I am completely stuck it seems and have no idea where to go from here.

Thank you in advance, I really need some help!

Is WordPress up to date. The get_custom_logo() function, which your theme can't find, was added in 4.5.0.

Hey Jacob,

Cheers for your response.

Im not entirely sure if i was running the latest version, but cant check as i cant login. It could be the problem. Do you know how best to resolve?

I am happy starting again from scratch. It happened when i switched themes from tesseract to illdy. I wanted to restore default settings in tesseract so had to deactivate first by changing themes. Then this all happened....

Thanks again.