From our friends at Response Point OEM Aastra:

Aastra Telecom is pleased to announce the availability of software maintenance release 2.4.1_RP.1014.  Available for download from the AastraLink RP website, this release offers a fix to the Call Park issues customers experienced when attempting to park a call on phones with multiple Lines/Users.

Please visit www.aastralinkrp.com and click on Software Downloads Area to obtain the new firmware