Hi Jorge,
This is the download page for the SQL Anywhere 11 developer edition:
https://global.sap.com/campaign/ne/sybase/sql_anywhere_1101_developer_edition/index.epx
Please let us know if you are able to access the download successfully.
Also, you should keep in mind that version 11 is end-of-life and no longer being updated. Newer versions of SQL Anywhere should be able to access version 11 databases as well.
For reference:
v12: https://global.sap.com/campaign/ne/sybase/sql_anywhere_12_developer_edition/index.epx
v16: http://www.sap.com/campaign/na/usa/CRM-XU13-CST-SQLDEVEDM/index.html
v17: Welcome | SAP
Thanks,
Mikel