TiddlyWiki5 is under rapid development at the moment, moving through a series of stages from alpha, via beta into a stable release.
The last remaining improvement before TiddlyWiki5 moves to beta is an easier upgrade mechanism.
During the beta TiddlyWiki5 will be practical for cautious everyday use but as we perfect the product there will occasionally be situations where we have to make changes that are not backwards compatible. These occasions will be clearly marked in the release notes.
The following additional features are planned or under consideration for implementation during the beta:
[img[url]]for remote image embedding, and
[ext[url]]for explicit external links
TiddlyWiki5 will leave beta and become a full release early in 2014. That is the point at which it is declared stable enough for general use. It will continue to improve and evolve after this point, although constrained to remain backwards compatible so that plugins and content created for version 5.0 will continue to work into the indefinite future.