Technology in 2019 has many ways of augmenting the human body, for example: hearing aids, pacemakers, artificial hips, breast implants, artificial spine discs, coronary stents and even artificial eye lenses. In addition to that there are many different kinds of prosthetics, even thought controlled.

Presumably the next big step will be all artificial organs, combined with advanced prosthetics, and humanity will enter a cybernetic era.

Assuming that at the peak of cybernetics era, the nanotechnology is perfected to the point where humans don't need surgeries that replace human organs and body parts. Instead, the nano robots that are always present in the blood stream instantly repair any damage to all organs and body parts and augment the human body, greatly increasing all capabilities.

Question:

What would be the next step after nanotechnology, and why?

(for example: could nano robots be replaced with some kind of DNA programs that are immune to EMP weapons in the wars of the future?)

Picotech and Femtotech

If you define the technologies available by the scale of engineering that is being supported, then of course the next stage involves Picotech:

technology or set of technologies that rearranges matter on the picoscale with something analogous to nanotechnology's scope and precision. It would supposedly allow not only precision arrangement of atoms but even arrangement of their internal states, leading not only to enhanced control over natural chemical reactions but to the creation of entirely novel atoms and molecules, including some stable and useful forms of exotic matter.

And after that of course would be Femtotech:

a technology or set of technologies that rearranges matter on the femtoscale, with something analogous to nanotechnology's scope and precision. Femtotech would supposedly allow precision arrangement of the elementary particles that make up atoms. This would supposedly allow such things as transmutation of elements without the use of massive facilities or the release of radiation, the creation of various kinds of exotic stable or metastable elements and other fantastic effects.

That’s a tough question... especially because some of them are questioning the human nature at its core. But as can be seen ..the human strives for any enhancement possible to perfect itself. At some point it might be possible to replicate our brain to such a degree that existence itself becomes a question mark if it really is just like a picture but just more complicated. The body at that point would become somewhat unimportant...if a clone can persist and individuality is more seen as a process of the development of that picture through time and each iteration and change made.
At that point humans might give their bodies any form they can think of and what is doable. Death would also be not a question anymore. Bodies might not be reproduced naturally anymore but be hulls that you can put your brains into. At that moment though, humanity ceased to exist.

Dark enough :0 ?

Task Specific Incarnations

As @WorldPeace suggests, brain replacement is the ultimate physical upgrade; allowing the consciousness to move from body to body and through the discipline of keeping backups and regular body maintenance, escaping death entirely.

Once that is achieved, although it will still be nice to have nanites onboard for impromptu repairs, the next big thing will be customization...

• Need superior vision for your detail-oriented job, replace your human-norm optics with our new EagleEye 3000 occular replacements. Unlike the simple eye-replacements of the past, this new offering replaces your entire host and includes increased neurological tissue dedicated to interpreting your new higher resolution world view in real time and massive amounts of storage so that you never forget the details.




• Going on a more sensual vacation, why not ride in a new host with ten times the normal pleasure receptors. Every nerve in your new body is optimized for your enjoyment.




• Joining the latest Martian archaeological team, only a fool would leave Earth in less than a BioDome III fully sealed and self sufficient host. Models available for week-long, month-long and even year-long adventures between replenishment breaks. Fully radiation and vacuum resistant or your money back.

"Ship of Theseus" brain replacement

(The details are here). If you have nanotechnology and picotechnology, you can work at a scale below glial cells and neurons. This allows to record and "decode" the operation of every single neuron, one a a time. Each new "nanoneuron" would interface with either existing biological neurons or other nanoneurons.

A single neuron's firing "rules" are quite straightforward (we know this from experiments on organisms like Planaria and freshwater snails). Our problem now is that complexity scales up so quickly that it's impossible to decode any significant neural circuit from above its scale. Nanoneural machines would not have this problem, and they could replace the brain one neuron at a time, leaving it working exactly as before.

But now the brain's state can be analyzed, transmitted, and saved. Also, defective or damaged neurons can now be replaced from backups. New neurons can be added, once the energy budget limit that dictates brain size has been removed. Once all neurons are actually nanomachines, their "clock" might safely be increased.

With a nanonic brain and a suitable body, man can now become immortal - as well as perhaps increasing his "natural" intelligence and controlling his body.

Darker possibilities include that of analyzing a brain state in search of the roots of some given convictions, beliefs, and loyalties - either to verify they're there, ensure they won't change, or ensure the opposite.