The core OpenGL ES 2.0 spec does not require it.
It does define an extension, though, which is similar to the one required in GL3 (apparently it's less flexible but I don't know the particulars). It's supposed to be covered by the same patents, though. OES_TEXTURE_FLOAT
Although optional, it seems it is expected to be present and so it might cause issues with applications that expect it if they aren't coded very well.
From Khronos regarding the OES extensions:
OpenGL ES extensions that have been approved by the Khronos OpenGL ES
Working Group are summarized in this section. These extensions are not required
to be supported by a conformant OpenGL ES implementation, but are expected to
be widely available; they define functionality that is likely to move into the required
feature set in a future version of the Specification.