Sorry for my English.

On my test bench, "trial and error method" i conducted research upgrading to oxwall 1.5. May be this trick can help other peoples exclude some errors 500.

Don`t forget to back up all your site files and MySQL database.

1. Download "upgrade pack 1.5" from this and unzip into some dir (for example: "new_oxwall") .

2. In the directory "new_oxwall/ow_includes" delete the file "config.php" 

3. In "config.php" of your site change "DEBUG MODE" and "DEV MODE" from "false" to "true".

4. Copy all files from unziped "upgrade pack" to directory of your site.

5. Go to the URL: "www.your_site/ow_updates". You will see message that system upgraded.

6. Again go to URL: "www.your_site/ow_updates" or hit "F5" on keyboard.

7. In "config.php" of your site change back "DEBUG MODE" and "DEV MODE" from "true" to "false".

8. Go to main page of your site.

This hoodoo can help exclude "error 500" after upgrade. 

Trick for "error 500" in plugins page.

1. If plugin of your site return "error 500" go to OXWALL STORE and download current version of plugin.

2. Unzip and copy plugin to your "ow_plugins" directory with replace.

3. Go to Admin-page and if you can see notice to upgrade plugin click button "UpgradeDB".

4. If you can`t see notice to upgrade plugin -> go to "step#5"

5. Go to main page and check plugin work.

While that is all.