[iRedMail 1.2 Upgrade] lber.h: No such file or directory

==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.1
- Deployed with iRedMail Easy or the downloadable installer? Downloadable installer
- Linux/BSD distribution name and version: CentOS Linux release 7.8.2003 (Core)
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): LDAP
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? Yes, 4.3 (LDAP)
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Hi,

I'm trying to upgrade to iRedMail 1.2 and I've just started with the 'Upgrade iRedAPD' section and it is failing to build python-ldap. The full output is in the attached log file.

  In file included from Modules/LDAPObject.c:3:0:
  Modules/common.h:15:18: fatal error: lber.h: No such file or directory
   #include <lber.h>
                    ^
  compilation terminated.
  error: command 'gcc' failed with exit status 1

Am I missing a package? I appreciate any assistance.

Thanks