Attachments can be configured in the app. To do so, as an administrator, go to Administration then System parameters.
In the Attachments block:
1. In the white list for file upload, complete extensions to allow, separated by commas. By default, the following extensions are indicated: txt, doc, xls, ppt, docx, xlsx, pptx, odt, ods, odp, pdf, xml, png, jpg.
2.In the upload limit size in bytes, enter the maximum size allowed (by default 4 000 000)
3.In the upload limit size of import file in bytes, enter the maximum size allowed (by default 2 000 000)
If you are using a MySQL database, don't forget to check max_allowed_packet=X property (where X is the max authorized size of attachments by Squash. By default, the application is set to 2Mo,ie X=2M) in the MySQL configuration file (my.cnf ou my.ini).