Filter Plugin Issue

Hi,

the issue I am having is that when selecting the attributes filter e.g. brand,
if I select 2 brands lets say it won’t show up any items even if there are items in the those attributes,
e.g. select Dell and Lenovo,with both have multiple in it, it shows no results,

I believe this is happening because our plugin is slightly out of date,

new update adds change in url
from e.g. ?filter_brand=dell%7Csamsung
to e.g. /?wpf%20filter_brand=dell%7Csamsung

which makes this work,

but I have tried to update to the latest version and I get
‘There has been a critical error on this website.”

but I’m not sure how to fix this?
have you seen this before

if you can let me know please

Thanks,
Gavin

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