The KEYFILE.TXT is the license for installing a particular version of software and protocol supports for that version. The keyfile is locked to a particular unit by serial number. Because of this software keys for system "A" cannot be used to install on system "B". Each key contains the software part number it is for, the version and an encrypted section. An example would be: 7KK1220-0SC1 V4.0=CE6S5 L4DS2 P9TRC GZN6W 4GBMS 08AHK 6AU4P ASLC1 This key is for version 4.0x of the K1297-G20 main application. Associated to the main application each protocol support or application package has it's own version. For example: 7PK1221-6GB1 V1.8=3T2U1 DN0L2 FR67F 2191B 0R272 0R2AZ UE1FH WC7A7 This key is for GPRS Gb Interface supports V1.8x. Notice the "x" item at the end of the version. This place mark can have a value of 0-9 for "updates" to this application. If the application "upgrades" at a new release of the primary software i.e.. V1.9x then a new key element would be needed for installation.