If you are upgrading from release 1.0.0RC6 or up you DO NOT need a dump/reload.
Upgrading from older releases requires a dump/reload. See the upgrading chapter for more informations.

Fault tolerant btree ops
Memory leak plugged in pg_error
Rtree index fix
Cleaner build scripts (avoided mix of CFLAGS and CXXFLAGS)

New index creation capabilities in loader (-I switch)
Initial support for postgresql 8.1dev