Got 2 job offers, confused which to choose.
1- old tech high salary
2- new tech a bit low salary

Depends on what you need.
If you need money, go for that.
If you will survive with what the other job pays, go for the newest tech.

Which one are you more familiar with? Old or new?

@forkbomber Wow we replied at the same time.

Always chose self improvment over salary. Because nothing good comes out of the comfort zone.

Yeah, take less money because the stuff you'll learn will help you earn more in the future. Doing the same thing, you're not going to gain any new skills so if you look in a few years time, you'll be behind.

I'd say it also depends on what you think the potential of the new tech... If you think the industry is going to be headed in that direction, or you can determine that the newer tech gives some sort of objective advantage, I'd say give that a shot. Otherwise, there's not really a good reason to forfeit salary for the latest tech

old tech - low expectations, might go surprisingly well
new tech - high expectations but they might not be there yet and still use low tech on 90% of their stuff and guess who will have to work on that 10%

happened to me every time, been a contractor for 10 years

What is the {old,new} tech?

old tech: get more money, buy new tech

I have made this choice recently. I was in a paid job good with very good salary and advantages. But I was thinking "working in a technologic job as ours, on old tech, will probably lead nearly nowhere or stuck me in my future...". The choice was the same as yours, first it depends on your salary need. But you have to take into account your career.

I chose new tech ;) If you can live with low salary, then it can only grow! :) 7 months after, I'm really enjoying my job and the techs! ;)

I'd go for the newest one too, because if it becomes really important in the future, it will probably become the fundamentals of even newer technologies, also, you would likely be able to aspire for a higher salary.
On the other hand, old tech hardly becomes source of trending tech.
Lastly, on my very personal point of view, the people concerned about creating new technologies often try to simplify the job the actual technologies already do. This means to me learning (which I deeply enjoy) something that will be useful for me in the future; and getting my job done easier and smoother

@jstaiyo what percentage of new tech do you think succeeds? What is the average lifespan for a new programming language, for instance?

@ReturnVoid very low indeed while old tech is well paid and the fewer devs with that knowledge, the higher their salaries of course. But, what when the company finally decides to make an update?
a) you'll suffer adjusting to a very big change.
b) you will be out there knowing something nobody uses anymore.
In the case of non succeeding new tech the risks are probably the same, BUT it has a chance of being successful and then there is a growth opportunity which does not exist when talking about old tech.
Besides, sometimes you just know.
I know, at least in Mexico, COBOL will be a source of work for several years in banks.
I know people will be speaking about angular for the next three years or more

What about advancement possibility? And which one will help you more if you move on to other job? Which one you think you will be happier?

It's not just money, try to write down each pro and cons and I think you can decide for yourself.

It depends on 'you live for money' or 'you live for happiness'. Old is boring, new is adventure.

Make a list of all the things that are important to you for job, environment, future opportunities, etc. Using that list write pros and cons of both positions. Give points for pros. Grade both, whichever one gets higher points wins. This way you've made a calculated decision on your own.

@Hakii
Well actually its about the version, One company wants me to work on Rails 3 version. The other(with low sal) wants me to work on Rails 3 but eventually will be exploring new JS frameworks with advanced Rails 5 projects...

@Heveabrasilien how can i decide that?

@bdonald 👍🏼👍🏼👍🏼

@talha the old on will not move to new rails? Like 4 or 5

@sgoten They will, but rails 3 project will go on for 7-12 months...

@talha Indeed.. It's quite similar and not so old right ?
In my case, it was switch from Java ee 6/7 with Struts 1 to C# MVC with all the JS framework I'm want/need to use.. :)

How is rails old tech? I thought you meant a PDP11 or something

@spl0 not rails, Rails 5 is new and rails 3 is quiet 2-3 years old

Won't the old become obsolete? And the newer the next big thing?