document this stuff. Nobody reads loooong changelog ;).
--- /dev/null
+quagga-0.97.0
+
+* Router advertisement syntax is changed. In usual cases (if you didn't do
+ any fancy stuff) it's enough to change lines in configuration from:
+ "ipv6 nd prefix-advertisement X:X:X:X::/X 2592000 604800 autoconfig on-link"
+ to:
+ "ipv6 nd prefix X:X:X:X::/X"
+
+ All router advertisement options are documented in texi documentation.
+