soy nivel 31, pero no puedo mejorar los equipos, que nivel necesito para hacer las mejoras.

It reads.

I am level 31, but I can not improve the equipment, what level I need to make the improvements.

Pippin was asking what might be a related question, and I know  in the past ,others have complained about the process.

I would need to go back and check ther specific text, but the table published above talks about a MAXIMUM chance of the equipment being upgraded,  so unless this is a bad translation ,a deliberate sleight of hand, or I am reading incorrectly, to me this suggests there is no guarantee at all that the upgrade will happen, and that there is some MINIMUM chance  of success.

This being the case, this MINIMUM  chance figure would be of more significance to players.

If 100%  means the conversion will happen, the word maximum needs removing from the text as it's misleading and superfluous.

Pippin's addition to his post confirms the first 3 levels are 100% guaranteed.

Though I accept  you want to clarify  the reducing success rate, I still think it should read 'chance of success 'X'%.'

I was making improvements with no problem at level 26,  (provided it says 100% chance of success - which it does most of the time).