Ok so im using unreal engine 4.8 and i would like to know if there is a way i can open my project in unreal engine 4.11 and other new engines that may come out.
You should be able to open them, the rest dependso n what your project uses and what was changed. There is possible that some blueprint nodes may broke but in most cases it should be ok. I recommand to update engine version by version, the ealier you update to newest version the less fixing you need to do in one time.
In C++ you will get warnings when some things are deprecated and may change in future and you should treat them as errors, by fixing them you will make transition process a lot smoother, sometimes project will build without single change needed. Sometimes (and i had such case with 4.10->4.11, but it was quite low level stuff) some things may change without warning then you need to figure out yourself what change, it good to check API refrence for updated stuff. There also updates that don’t bring any API changes and build without any issue (thats the case between 4.8-4.10).
You can install more then one engine version, you that to test out how your project works in specific version