upgrade.php not in said directory. Other file giving error

Upgrading from 1.5.3.1 to 1.5.4.1

I don't see the upgrade.php file in the install directory. I did find one in the install/model/ directory, but when I go to that file, I get this error:

Fatal error: Class 'Model' not found in /home/content/80/8431380/html/firstchurch/store/install/model/upgrade.php on line 2

Please help.... Thanks!!

Let me now if you solve your problem. I'm having the same problem.

Same problem here.. Upgrading from OC 1.5.1.3 to 1.5.4.1.
There is no upgrade.php file in the install directory, however there is an upgrade.sql file which updates the database structure.

Any help guys?

When upgrading to 1.5.4.1 the config.php > 0 and install/index.php loads the upgrade.sql
Only when you did not overwrite your config files as stated in the instructions.

Cheers!
The upgrade readme in the download says this:
STEP 5. Browse to http://www.yourstore.com/shop/install/upgrade.php

This got me confused.

Simply navigate to

http://www.yourstore.com/shop/install/

and it will do the trick.