The default keyexchange mode ‘ike’ is changing with release 4.5 from ‘ikev1’, thus commemorating the five year anniversary of the IKEv2 RFC 4306 and its mature successor RFC 5996. Added new ctr, ccm and gcm plugins providing Counter, Counter with CBC with CBC-MAC and Galois/Counter Modes based on existing CBC implementations. New pkcs11 plugin brings full Smartcard support to the Ikev2 utility using one or more PKCS#11 libraries.
Source: https://thehackernews.com/2010/11/strongswan-v450-new-version.html