openLDAP config broken after Ubuntu upgrade (20.04 -> 22.04)

I have problems with openLDAP after updating from Ubuntu 20.04 to 22.04. If I use slapcat after the update it leads to the following error:

olcAttributeTypes: value #0 olcAttributeTypes: Duplicate attributeType:
"1.3.6.1.4.1.42.2.27.8.1.1"
config error processing cn={4}ppolicy,cn=schema,cn=config: olcAttributeTypes: Duplicate attributeType: "1.3.6.1.4.1.42.2.27.8.1.1"
slapcat: bad configuration file!

The folder /etc/ldap/slap.d contains still all configurations files. Before the Ubuntu update everything worked just fine. Any ideas?

*Edit: Configuration file exported with slapcat -n 0 -l filename.ldif. Part that leads to the error:

dn: cn={4}ppolicy,cn=schema,cn=config
objectClass: olcSchemaConfig
cn: {4}ppolicy
olcAttributeTypes: {0}( 1.3.6.1.4.1.42.2.27.8.1.1 NAME 'pwdAttribute' EQUALI
 TY objectIdentifierMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.38 )
olcAttributeTypes: {1}( 1.3.6.1.4.1.42.2.27.8.1.2 NAME 'pwdMinAge' EQUALITY 
 integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.
 1.27 SINGLE-VALUE )
olcAttributeTypes: {2}( 1.3.6.1.4.1.42.2.27.8.1.3 NAME 'pwdMaxAge' EQUALITY 
 integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.
 1.27 SINGLE-VALUE )
olcAttributeTypes: {3}( 1.3.6.1.4.1.42.2.27.8.1.4 NAME 'pwdInHistory' EQUALI
 TY integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.1
 21.1.27 SINGLE-VALUE )
olcAttributeTypes: {4}( 1.3.6.1.4.1.42.2.27.8.1.5 NAME 'pwdCheckQuality' EQU
 ALITY integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.11
 5.121.1.27 SINGLE-VALUE )
olcAttributeTypes: {5}( 1.3.6.1.4.1.42.2.27.8.1.6 NAME 'pwdMinLength' EQUALI
 TY integerMatch ORDERING integerOrderingMatch  SYNTAX 1.3.6.1.4.1.1466.115.
 121.1.27 SINGLE-VALUE )
olcAttributeTypes: {6}( 1.3.6.1.4.1.42.2.27.8.1.7 NAME 'pwdExpireWarning' EQ
 UALITY integerMatch ORDERING integerOrderingMatch  SYNTAX 1.3.6.1.4.1.1466.
 115.121.1.27 SINGLE-VALUE )
olcAttributeTypes: {7}( 1.3.6.1.4.1.42.2.27.8.1.8 NAME 'pwdGraceAuthNLimit' 
 EQUALITY integerMatch ORDERING integerOrderingMatch  SYNTAX 1.3.6.1.4.1.146
 6.115.121.1.27 SINGLE-VALUE )
olcAttributeTypes: {8}( 1.3.6.1.4.1.42.2.27.8.1.9 NAME 'pwdLockout' EQUALITY
  booleanMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.7 SINGLE-VALUE )
olcAttributeTypes: {9}( 1.3.6.1.4.1.42.2.27.8.1.10 NAME 'pwdLockoutDuration'
  EQUALITY integerMatch ORDERING integerOrderingMatch  SYNTAX 1.3.6.1.4.1.14
 66.115.121.1.27 SINGLE-VALUE )
olcAttributeTypes: {10}( 1.3.6.1.4.1.42.2.27.8.1.11 NAME 'pwdMaxFailure' EQU
 ALITY integerMatch ORDERING integerOrderingMatch  SYNTAX 1.3.6.1.4.1.1466.1
 15.121.1.27 SINGLE-VALUE )
olcAttributeTypes: {11}( 1.3.6.1.4.1.42.2.27.8.1.12 NAME 'pwdFailureCountInt
 erval' EQUALITY integerMatch ORDERING integerOrderingMatch  SYNTAX 1.3.6.1.
 4.1.1466.115.121.1.27 SINGLE-VALUE )
olcAttributeTypes: {12}( 1.3.6.1.4.1.42.2.27.8.1.13 NAME 'pwdMustChange' EQU
 ALITY booleanMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.7 SINGLE-VALUE )
olcAttributeTypes: {13}( 1.3.6.1.4.1.42.2.27.8.1.14 NAME 'pwdAllowUserChange
 ' EQUALITY booleanMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.7 SINGLE-VALUE )
olcAttributeTypes: {14}( 1.3.6.1.4.1.42.2.27.8.1.15 NAME 'pwdSafeModify' EQU
 ALITY booleanMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.7 SINGLE-VALUE )
olcAttributeTypes: {15}( 1.3.6.1.4.1.4754.1.99.1 NAME 'pwdCheckModule' DESC 
 'Loadable module that instantiates "check_password() function' EQUALITY cas
 eExactIA5Match SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 SINGLE-VALUE )
olcAttributeTypes: {16}( 1.3.6.1.4.1.42.2.27.8.1.30 NAME 'pwdMaxRecordedFail
 ure' EQUALITY integerMatch ORDERING integerOrderingMatch  SYNTAX 1.3.6.1.4.
 1.1466.115.121.1.27 SINGLE-VALUE )
olcObjectClasses: {0}( 1.3.6.1.4.1.4754.2.99.1 NAME 'pwdPolicyChecker' SUP t
 op AUXILIARY MAY pwdCheckModule )
olcObjectClasses: {1}( 1.3.6.1.4.1.42.2.27.8.2.1 NAME 'pwdPolicy' SUP top AU
 XILIARY MUST pwdAttribute MAY ( pwdMinAge $ pwdMaxAge $ pwdInHistory $ pwdC
 heckQuality $ pwdMinLength $ pwdExpireWarning $ pwdGraceAuthNLimit $ pwdLoc
 kout $ pwdLockoutDuration $ pwdMaxFailure $ pwdFailureCountInterval $ pwdMu
 stChange $ pwdAllowUserChange $ pwdSafeModify $ pwdMaxRecordedFailure ) )
structuralObjectClass: olcSchemaConfig
entryUUID: cb6c1fd8-9c5b-103c-96b7-758a4a648933
creatorsName: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth
createTimestamp: 20220720094054Z
entryCSN: 20220720094054.645718Z#000000#000#000000
modifiersName: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth
modifyTimestamp: 20220720094054Z

Best regards, Arne

Here is an excellent instruction how to find your old data from (automatic apt) backups, and how to manually migrate your data from 2.4 to 2.5 in an event of any error:

https://discourse.ubuntu.com/t/service-migrating-from-openldap-2-4-x-to-2-5-x/23807

I got the same error. It's caused by the password schema being incorporated to the core. The fix is to manually remove the complete section (starting from empty line and ending to an empty line) from your backup cn=config.ldif referring to the offending pwdAttribute .. pwdPolicy. After this follow the instructions.

OpenLDAP 2.5+ now ships the ppolicy schema hard-coded in the overlay slapo-ppolicy. So you have to remove this schema from your cn=config data before reloading it (your entry cn={4}ppolicy,cn=schema,cn=config).

See also second paragraph of upgrade docs section B.2. ppolicy overlay.