Generally, this is the hierarchal order in which templates will work for the custom post type.
single-{post-type}-{slug}.php – (Since 4.4) First, WordPress looks for a template for the specific post. For example, if post type is product and the post slug is dmc-12, WordPress would look for single-product-dmc-12.php.
single-{post-type}.php – If the post type is product, WordPress would look for single-product.php.
single.php – WordPress then falls back to single.php.
singular.php – Then it falls back to singular.php.
index.php – Finally, as mentioned above, WordPress ultimately falls back to index.php.
I have created this template:
single-theme.php
But the posts pages of the theme CPT are not picking up this template? what could be the issue?
If needed I can update my question with the full CPT function.
I am using this in CPT can this be a culprit:
'capability_type' => 'page',
?