Yes, you can. That's a very common use cage.
To cite from the official v16 docs FAQ page:
Can I install and run two different versions of SQL Anywhere on the same computer?
Yes, you can install multiple major versions of SQL Anywhere on the same computer. For example, SQL Anywhere 9.0.2, 10.0.1, 11.0.1, and 12.0.1 can all be installed and run independently.
However, you must use caution when starting a SQL Anywhere executable that has the same name in multiple versions (for example, dbisql or dbinit) to ensure that you are starting the correct version of the application. You can either specify the full absolute path using environment variables such as SQLANY16, or ensure the version of SQL Anywhere you want is specified first in your path.
19 May '14, 03:47