You can update theme by this ways:
1. Upload Theme Folder Via Ftp To Your Site
Following these steps below to upload theme via FTP:
Step 1. Login your FTP account via an FTP software to access your host web server.
Step 2. Unzip onelms.zip file.
Step 3. Upload the exacted theme folder onelms to wp-content/ themes folder.
Step 4. Active the theme in Dashboard >> Appearance >> Themes.
Step 5. Enable Thim Core to activate the core of OneLMS and start importing demo data process.