Canonical announced that the LPIA (Low-Power Intel Architecture) architecture would no longer be supported.
Canonical drops support for LPIA because users are not interested in LPIA.The developers decided to retire it.
"During a discussion at the Lucid Lynx Ubuntu Developer Summit on the future of the architecture, all participants agreed that retiring the architecture would be a net benefit to Ubuntu. Several participants volunteered to investigate the performance and power consumption of lpia vs. i386, with the intention of bringing these improvements forward in future releases." -- Steve Kowalik said in the official announcement.
Canonical added support for LPIA a couple of years ago and it was used by the Ubuntu Mobile project, for the recent Intel mobile CPUs with support for this lower-power architecture. The LPIA or Low-Power Intel Architecture is similar to the IA32 (also known as i386 or x86) architecture, but with dissimilar compile-time optimizations. However, Steve Kowalik added that the Intel CPUs would work very well with IA32: "Recent announcements by Intel indicate that processors supported by the lpia architecture are expected to remain compatible with the IA32 instruction set, so there is a reduced expectation of the need to retain a separate architecture to address future requirements. As of 9.10, lpia and i386 share the kernel configuration, reducing most of the benefits potentially available in previous Ubuntu releases."
Support for the LPIA architecture will be provided on the Ubuntu 9.10 until April 2011.LPIA users will be unable to upgrade to Ubuntu 10.04.
Check Official announcement from here