如何更改Drupal自定义字段的最大字符长度？

Question

I created a field (in Drupal) where I would insert my Product ID. I set that field to allow a max character length of 10 - at the time that is what all of Shopify's Product ID lengths were 10.

I'm using Shopify API to generate some content on my Druapl Website.

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I would take a Product ID, Put it into a a field , and render the content - Wallah!.

Unfortunately, for me... Shopify ran out of 10 digits and is now using 11 for their product Ids.
Even more unfortunate, Drupal doesn't allow me to edit this field from 10 max char length to 11.

I would have to create another field which would cause me to lose all previous work.

What I tried:
I tried concatenating two fields to add the remaining one character. I don't think I did it right though or knew where to start.

Answer 1

Use this module

But This project is not covered by the security advisory policy. Use at your own risk!

https://ftp.drupal.org/files/projects/field_maxlength_alter-7.x-1.x-dev.zip

Install this module and go to field setting tab on your field and increase the field length, don't decrease otherwise you lost old data.

but keep you site db first to use this module.