Unfortunately your attribute seams to be of type varchar
and here you have a database restriction to 255 characters in for the value
field of type varchar in the corresponding eav table catalog_product_entity_varchar
.
You need an attribute of type text
in order to store more data since then you will have a value
field of type text with a restriction of 65,535 bytes in the corresponding eav table catalog_product_entity_text
.
Now that's theory. Unfortunately Magento does not support the change of attribute type for good reason. Although there is a way doing that by database changes for varchar to text, I don't recommend that here - although for good reason :-)
I would suggest the following:
- Create a new attribute "features2" of type text
- Export the features for all existing products
- Import the data for all existing products into the new created attribute
- Rename the attributes so that the new created attribute will be named "features" (you may also delete the old attribute after that)
Of course you should test that approach in a test / stage environment before applying the changes in production.