No new topic can be added

[dz_khelifa]

A problem, I cannot add a new topic
And some forum features do not work

When I try to add a new topic, a blank page appears to me and the transfer process stops (pictures in attachments)

Used copy php 5.6
vb 3.8.7

[Mark.B]

For php 5.6 you will need to upgrade to vBulletin 3.8.11 which was the final release in vB3 series.

[dz_khelifa]

When I upgrade to version 3.8.11, do I need to upgrade style as well? What will I restore style to php 5.6

[Mark.B]

When I upgrade to version 3.8.11, do I need to upgrade style as well? What will I restore style to php 5.6

The style should be fine, nothing changed between 3.8.7 and 3.8.11 other than php compatibility changes and very minor bug fixes.

Always have a database backup though, just in case.