Can I, or should I make a PRSI Voluntary Contribution for Tax Year 2017?

Here is my situation.

I had been in employment and paying PRSI for almost 20 years.
I lost my job in the middle of 2016.
In 2017, I filed my return for Tax Year 2016 and paid Income Tax, PRSI, USC etc. as normal.

I struggled to find a job in 2017, and when I filed my return for Tax Year 2017, my income was below the threshold, and I ended up paying zero PRSI for 2017.

For Tax year 2018, dividend and interest income put me above the threshold and so I paid the minimum €500 in PRSI.

My questions are:
1. What impact, if any, would a "missed" year of PRSI contributions have on any future state contributory pension?
Does it jeopardise the payment of this pension, or simply reduce the amount?

2. Is it possible to make a PRSI Voluntary Contribution for Tax Year 2017 at this stage?
If so, do I simply send Revenue a cheque for €500 with a letter explaining ?

I noticed this form on the Revenue website.
Should I use this form?

For Tax year 2019, I am back in full time employment and paying normal PRSI on salary monthly.
If anyone is familiar with this type of scenario and can advise, I would appreciate it.

C.

Unfortunately nobody knows. The current situation would mean it would depend on when you actually first started working in Ireland. The alleged new system coming in soon would mean that you would be paid 1/40 of a pension for every year you worked till retirement. If you are about 40 now then it probably wouldn't make sense to pay the stamp as we don't know what or how the sytem will pay out the pension. Only probable thing is that people who have never paid PRSI will get looked after by getting the same as someone with 40 years paid.

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Check your mygov.ie online to see if you have received PRSI credits. If you are out of work you should have received some.