GUI update via Diagnostics page not available

[ttrvl]

After updating to 5.0.3 feature "Check for update" not showing at "Diagnostics" page.

Steps to reproduce the behavior:

1. Go to 'Diagnostics'
2. First text will be Diagnostics block instead of "Check for updates" or "Update available" message like before.

Screenshots
1st site:

2nd site:

Output of the diagnostics

Diagnostics
-----------
    Warning: Dropbox import not working. dropbox_key is empty.
    Warning: zend.assertions is disabled although Lychee is in debug mode. For easier debugging code generation for assertions should be enabled.
    Info: Latest version of PHP is 8.3
 

System Information
------------------
    Lychee Version (git):                    master (6fc6c10) -- Up to date (38 minutes ago).
    DB Version:                              5.1.0
    
    composer install:                        --no-dev
    APP_ENV:                                 production
    APP_DEBUG:                               true
    APP_URL:                                 set
    APP_DIR:                                 default
    LOG_VIEWER_ENABLED:                      true
    LIVEWIRE_ENABLED:                        true
    
    System:                                  Linux
    PHP Version:                             8.2.7
    PHP User agent:                          Lychee/4 (https://lycheeorg.github.io/)
    Timezone:                                Europe/Moscow
    Max uploaded file size:                  200M
    Max post size:                           100M
    Livewire chunk size:                     12.00 MB
    Max execution time:                      300
    MySQL Version:                           10.11.4-MariaDB-1~deb12u1-log
    
    exec() Available:                        yes
    Imagick Available:                       1
    Imagick Enabled:                         1
    Imagick Version:                         1691
    GD Version:                              2.3.3
    Number of foreign key:                   12 found.
 

Config Information
------------------
    version:                                 050100
    check_for_updates:                       0
    sorting_photos_col:                      taken_at
    sorting_photos_order:                    DESC
    sorting_albums_col:                      max_taken_at
    sorting_albums_order:                    DESC
    imagick:                                 1
    skip_duplicates:                         0
    small_max_width:                         0
    small_max_height:                        360
    medium_max_width:                        1920
    medium_max_height:                       1080
    lang:                                    en
    image_overlay_type:                      none
    default_license:                         CC-BY-NC-SA-4.0

Browser and system

Lychee installed on Debian Linux 12.4
Browser tried (windows): Firefox 121.0.1, Google Chrome 120.0.6099.225
Via mobile device same result.

Additional info

I have two sites witch Lychee (both on same server), both have same issue after updating to 5.0.3
One of instances I had updated by console with "git pull" and all other steps to 5.1.0 - no changes. (1st screenshot)
Second instance I decided to not update for testing means (if needed by) (2nd screenshot)

No errors showing in Lychee logs or webserver logs.

[ildyria]

I think I forgot to add that functionality in the v5 (as in, I forgot to add the button).