[Koha] Barcode length

[Pedro Amorim]

Hello everyone,

I have a question regarding barcode length in Koha.
I'm importing a new biblio database and some barcodes have length of 26 or
28 and so on.

Koha's database schema limits the barcode field in the items table to
varchar(20).

My question is:
Is it okay to manually alter this field length? As so:

*ALTER TABLE items MODIFY barcode VARCHAR(40);*

What sort of problems can this cause in the future? Do I have to apply this
change everytime I update Koha to a newer version?

Thanks a bunch,

Pedro Amorim