That's the point. I didn't update anything. And I did translate to spanish as indicated in the documentation:
administrator\language\en-GB\en-GB.com_spproperty.ini (this file include all main admin panel phrases)
administrator\language\en-GB\en-GB.com_spproperty.sys.ini (admin menu phrases)
And For front-end phrases i did this same process with following files:
language\en-GB\en-GB.com_spproperty.ini
language\en-GB\en-GB.mod_spproperty_search.ini
language\en-GB\en-GB.mod_spproperty_properties.ini
language\en-GB\en-GB.mod_spproperty_agents.ini
language\en-GB\en-GB.mod_spproperty_emi_calculator.ini
language\en-GB\en-GB.mod_spproperty_categories.ini
In order to be more precise, I'll merge this discussion here https://www.joomshaper.com/forum/question/2627 . I hope it will easy the process,
Best regards,