@bw123 In changelog for 5.7.4 it's mentioned as follows:

8. To improve database performance, the "Delete Log" function and the maximum number of logs have been removed, and the logs are stored in two separate tables. Logs within 30 days are in the Current Logs table, while those older than 30 days are dumped into the History Logs table, and those that exceed the History Data Retention setting of log will be automatically deleted.

https://community.tp-link.com/en/business/forum/topic/589730

  @S-K 

Thanks for that.  I never search for why it dissappeared.  I suppose TP Link could update that page where they reference that delete button with that fact that the newer versions of the Omada software doesn't have it.

  @bw123 Funny enough, I still get the "maximum number of logs reached" warning...