More general info on the MIFARE page.
(old) MIFARE DESFire
NFC Forum Type 4 Tag 1.0
Old specification for NFC Forum Type 4 Tag allowed to use DESFire but newer version of the specification needs to use MIFARE DESFire EV1. Most NFC-compliant devices recognize MIFARE DESFire -based Tags but support cannot be guarantee for all NFC devices.
MIFARE DESFire EV1
- DESFire EV1 8k has an EEPROM of 8192 bytes, of which 7936 are free for user
- DESFire EV1 4k has an EEPROM of 5088 bytes, of which 4864 are free for user
- DESFire EV1 2k has an EEPROM of 2528 bytes, of which 2304 are free for user
NFC Forum Type 4 Tag 2.0
From NFC Forum: Type 4 Tag is fully compatible with the ISO/IEC 14443 standard series. Tags are pre-configured at manufacture to be either read and re-writable, or read-only. The memory availability is variable, up to 32 KBytes per service; the communication interface is either Type A or Type B compliant.
NXP AN11004 (pdf) describes how to use a DESFire as Type 4 Tag.