Hello,
There is an issue and it is first reason that i can not use Ghost on my Turkish language websites. As you know Ghost adding headers text as an id for header. But when it contains turkish characters (üğİıçöş) its replacing them with a dash.
Example: <h2 id="nas-l-yap-l-r">Nasıl Yapılır</h2>
I believe it could be not good for SEO?
How can i control header ID’s that Ghost write them same as permalinks. ?(In permalinks it works good. “Nasıl Yapılır” becaming /nasil-yapilir)
Hey @Yilmaz_Sarac 
ID attributes in HTML elements have to be compliant with HTML spec where special characters are not allowed: https://www.w3.org/TR/html401/types.html#type-name :
ID and NAME tokens must begin with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").
I believe it could be not good for SEO?
Would be interested to see some reference proving this 
Non English characters in title replacing with smilar English character on url permalinks, but on header id’s, replacing with a dash (-). How can auto replace non-english characters in header id with smilar English character? Just like url structure.
Oh I see what you mean 
this is an interesting catch. Guess there should be no problem to use the same mechanism generating id attributes for H1/H2 elements in a similar way we do for slugs. Think @Kevin is the best person to ask about this behavior