Please share more information. I don't know what you exactly mean.

in joomla 3.6 my urls were like this: http://www.mydomain.com/category/id-article_name
but after joomla 3.7 it is becomes like this: http://www.mydomain.com/id-category/id-article_name

First go to back end and check if your menu item "category" is published.

i checked, it is published

... and any menu item associated with that category?

yes :(

Does old URLs work?

yes they do

i installed a text joomla 3.7 site with no component or plugin. it had the same problem. i use joomla "Use URL Rewriting" in global configuration.

there are also two other problem:
1- in article latest Module it adds category id too.
2- in menu if i go in one item, and then i want to go to another, url becomes like: http://www.mydomain.com/first-item-i-clicked/id-category/id-article
it adds first item to url

by text i meant test

I tried to reproduce that with all Joomla installations I own but failed. Are you really sure that you do not use any 3rd party components? Did you tried to re-download the joomla installer and update all files again to ensure the ZIP file is not broken somehow?

yes, as i told i installed even a new text joomla with no 3d-party. i use joomla "Use URL Rewriting" in global configuration, that's all i did.
i use php 7.0.18.
Apache
linux server
urls wont be short as joomla 3.6

It is weird.
I did a test. My steps:

1. Download zip from https://github.com/joomla/joomla-cms/releases/download/3.7.0/Joomla_3.7.0-Stable-Full_Package.zip
2. Extract.
3. Install without any testing data.
4. Go to backend and set "Use URL Rewriting" to yes
5. Rename htaccess.txt to .htaccess
6. Comment a few lines because my apache does not allow for that:

#Options +FollowSymlinks
#Options -Indexes

7. Go to backend and create article "Article Test" as featured in new created category "category".
8. Go to front page and I see my article with link: .../8-category/1-article-test
9. Now I create a menu item with type "Category List" and choose category "category" then save.
10. Go to front page again and I see link .../category/1-article-test

Everything works.

there are also two other problem:
1- in article latest Module it adds category id too.
2- in menu if i go in one item, and then i want to go to another, url becomes like: http://www.mydomain.com/first-item-i-clicked/id-category/id-article
it adds first item to url

There is an issue at #15336 which may also affected articles.

dear csthomas, that didn't work for me.
but i fixed it in this way:
create new categories
move articles to new categories
remove menus
create new menu and set menu item language to all

but it is really hard to do so. i had more than 500 articles, 20 categories and around 50 menu items.

Thank for response.
Because you mentioned about

... and set menu item language to all

I suspect this is the key.

I have created a short test on my test installation.
I went to backend, created a second article in second category and second menu item.
And everything was still working.
After I changed language from "All" to "en-GB" in "second category" menu item then I got you issue.

My conclusion
Menu item language has to be equal to category language.

the strangest thing was that without creating new categories and move articles into it, changing language wasn't the answer. is it a bug or i dont understand joomla multilingual feature properly?
i checked my whole site for 404 error pages. in print version, some categories or authors links are broken.

@infograf768 can you please have a Look at Conclusion of @csthomas: " Menu item language has to be equal to category language."

I am a bit confused here:
Is that site multilingual?
If it is not, then delete the en-GB content language (and all others) and never choose en-GB (or whatever content language) as this is totally useless (and apparently creates issues, which should be looked into as router related)

If it is multilingual, it may be an issue I can try to look into it.

@infograf768 no it was not a multilingual site, it just was active. thank you all dudes. i have some other joomla websites, i'll do the same (menu and categories languages to be equal) if there was any issue, i'll post it here.

i checked it was fine. thanks

@agerinteam Issue can be closed?

@franz-wohlkoenig yes dear

@agerinteam You can close your own issues within the issue where you can post a Comment or click the Close issue button.

Had the same issue after updating to Joomla 3.7. Solved it by enabling the "System - Language Filter" plugin (though it's not a multilingual website) and setting "Item Associations" to No. Note that I had previously followed the tip regarding the setting of all menu items, categories and articles to have the same language.

Thanks! I had solved by this way