XHTML Basic was defined by the W3C in 2000. Initially there was HTML, then XML came. XHTML is the evolution of HTML following the new rules defined by XML. XHTML Basic is a simple version of the full XHTML. Scope of XHTML Basic is to include the very simple and needed tags and then be extended with modules. See also Modularization of XHTML.
When the OMA defined WAP 2, XHTML-MP was part of that standard. In order to converge towards a more open and supported standard, the OMA decided to build XHTML-MP on top of W3C‘s XHTML Basic. We can say that XHTML-MP is a superset of XHTML Basic. You may also want to read What is XHTML-MP?
For these reasons, any device that supports XHTML-MP will also support XHTML Basic 1.0. You will often seen the XHTML content-type in the HTTP headers of a WAP 2 device.
XHTML Basic’s doctype:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN" "http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
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