While it’s not specific to MP6 (I am not following its development) and its CSS, to me your question sounds like “how to check that WP version is equal to greater than one some feature was introduced in?”.
So I would just examine content of $wp_version global. If it’s 3.8 feature then anything with fitting version has it.
Also from quick look at body classes in admin there is branch-3-7 class, which makes possible to target branch-3-8 (however cannot be targeted conditionally as anything >=3.8 since that’s not something CSS does).
Related Posts:
- What are the standard admin CSS id/class tags?
- WordPress admin stylesheet
- This CSS Stuffing Works, But Is This A Good Practice?
- How do I load a CSS style into WordPress admin area only?
- Load plugin scripts and styles only on plugin page
- How to fix admin stylesheet muck-up? [closed]
- Custom CSS In Admin Only For Certain Roles
- Modify CSS via Theme Control Panel
- Why are my styles being applied to the admin area?
- Adding another “Add Post” button to admin
- Enqueue and Dequeue from admin bar nodes
- admin_enqueue_scripts the same css file as wp_enqueue_style
- Fixed layout for admin section
- WordPress admin toolbar not loading styles after migration
- Black admin bar is being hidden by page elements
- WordPress Admin Thickbox: Remove Margins/Padding
- Admin Ajax is returning 0
- Add custom column to Users admin panel
- wp_verify_nonce vs check_admin_referer
- Add a Separator to the Admin Menu?
- How to determine whether we are in add New page/post/CPT or in edit page/post/CPT in wordpress admin?
- how to know if admin is in edit page or post [duplicate]
- Modal window from within WordPress admin
- Where in WP can I check history or log of updates of plugins etc?
- Adding a custom admin page
- How does admin-ajax.php work?
- How to remove entire admin menu?
- How do I remove dashboard access from specific user roles?
- Disable SSL / HTTPS for wordpress
- How can I speed up my WP admin section?
- How to pass parameters to admin_notices?
- Admin: very slow edit page caused by core meta query
- if admin is logged in
- Search posts by ID in admin
- How to Change the Default Home Page for the WordPress Dashboard?
- Setting admin edit panels & metaboxes positions and visibility for ALL users and admins
- Find out which moderator approved comment?
- The website cannot display the page
- How To Remove WordPress Version From The Admin Footer
- Sort pages in loop by admin’s page attributes order field?
- Edit “thank you for creating with WordPress” in version 3.3.1
- Hide other users’ posts in admin panel
- Set Default Admin Colour For All Users
- Editor Styles and Typekit
- Is it possible to create a WordPress tour? V3.3.1
- Securing Admin Accounts – Username Discovery
- is_admin() returns true when using admin-ajax.php from front end script
- How to save dismissable notice state in WP 4.2?
- How do I optimize a custom post type admin page with 25,000 posts?
- Settings API – adding setting fields dynamically?
- Disable Media Uploads to non Admin Users
- Allowing admin-ajax.php to receive “application/json” instead of “x-www-form-urlencoded”
- Can an admin check passwords of registered users?
- Notification that the admin is online
- Does wordpress create activity, update logs?
- sort child pages on admin
- How-to make the admin area mobile friendly [closed]
- How to remove list view from media library?
- How to disable the “Your site has updated to WordPress x.y.z” admin email?
- Plugin to remove Admin menu items based on user role?
- How to obtain the user ID of the current profile being edited in WP-Admin?
- 3.3: How do you hide the new dashboard welcome panel?
- Add my own button next to “Screen options” and “Help” in the admin
- WP List Table custom quick edit box – post meta data missing and columns change on submit
- Settings API – easiest way of validating checkboxes?
- Are there any action like ‘init_frontend’
- Should I use is_admin() inside ‘admin_init’ hook callback
- Custom admin email for new user registration
- Send Admin Emails to Multiple Email Addresses
- How do I set up the defualt page icon for admin menu?
- Prevent author from changing their posts if admin has modified
- Cannot access admin panel
- Make A WordPress Page Accessible To Admins Only, Redirect Other User Roles
- Disable all https in WordPress
- localhost/wp-admin on my local redirects to production site’s /wp-admin
- How to remove administrator role in settings -> general -> New User Default Role?
- Is there a more efficient admin search function/plugin?
- Can a users profile be put under the dashboard menu
- WordPress Admins or Roles per Page
- Styling Shortcodes in Visual Editor
- initial sort order for a sortable custom column in admin
- Showing WP_Error message with admin_notice action hook
- How to make a theme with more than one CSS file?
- WordPress admin screen very slow / timing out when editing or adding a new page/custom post
- Uploading files in admin panel?
- turn off new user registration emails
- Redirect Admin User in Dashboard
- Send automatic mail to Admin when user/member changes/adds profile
- Create un-removeable user
- Get current active wp color scheme
- Read only capability for custom post in admin area
- WordPress Admin back-end – advanced options page?
- Cannot login to WordPress Admin with SSL terminated load balancer
- How can ‘admin_email’ be set?
- Set Featured Image programmatically (in admin) with JavaScript?
- Disable the post save process completely
- use add_settings_field properly?
- How to change WordPress default strings?
- How can we customize the logo and some text on the welcome screen?
- front end logo upload like happytables