Effective on the [U.S.-formatted] dates listed below, IBM will withdraw support from the following product releases licensed under the IBM International Program License Agreement:
5724-E70 6.5.[x] 4/30/09 IBM Lotus Notes and Domino
55724-E89 6.5.[x] 4/30/09 IBM Lotus Enterprise Integrator
This means that 6.5.6 is the last maintenance release for the 6.5 codestream. Mainstream technical support for Notes/Domino 6.5.x (as well as LEI 6.5.x) will end on April 30, 2009. Support extensions are available for up to two years following that date (through April, 2011). The Notes/Domino 6.x codestream first shipped in September, 2002.
Regarding the following technote IBM seamed to push the end of service for 6.5.x to 2010.