I'm a bit surprised to find that the developers are working on TikiWiki 1.10. This does not confirm with any version numbering method I have ever seen.
TikiWiki 1.9 = TikiWiki 1.90. You cannot now change it to what you had meant, namely 1.09. It is therefore not followed by TikiWiki 1.10, but by TikiWiki 2.0(0).
I know I'm being a pain in the arse but really... don't do 1.10. It looks silly and unprofessional.