.htaccess – moved to root – redirect

it’s possible to do that, but (depending on how many old posts you have) can be a real pain. if it’s a large site your best bet would likely be just re-direct everything to the root of the new site like:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule . https://new.site.url/index.php [L]
</IfModule>

you could also get fancy, and change things to a 301 permanant re-direct, but that’s the easy way. in order to map old posts to new ones you’d need to have a separate rule for each (assuming you’re using some type of pretty/name based permalinks, if they’re /p?## kinds of links anyway, then you could get away with one rule for each type of request (e.g. pages, archives, categories, etc)