I have installed this script successfully on my server. I found so many error & bugs.
- I can not add customer without phone number & email address.
- I can not delete my company which I have created.
- I can not change to my invoice sequence.
- When I am creating invoice & adding customer same time & if I missed one information to enter in customer section, it disappear few form field & showing error.
- All my customer does not have email address and phone number.
- Invoice logo is too small.
- MSAnsweredHello, The download and the demo are exact same. - 
If you need to remove validation for required fields, you will need to modify the item code. The help folder has general guide. 
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Yes, there is no option to delete the company. This is to avoid any data loss, you only have the option to edit/update the company. I will check in future dem to add the delete option for company. 
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The invoice number are the id column of the database tables. You can change the Auto Incrementfor table as you need.
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The fields value should be set back with error. I will check this. 
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You will need to follow the instructions from the help folder to remove the required validation. 
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The invoice logo is 300x80 px, if you need to change this, you can edit the app/controllers/Settings.phpand change$config['max_width']&$config['max_height']as you need.
 Thank you 
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