[horde] Horde 6 Error Class "Horde_Crypt_blowfish" not found

[Horst B Simon]

Hi,

I tried again to install Horde 6, using apache 2.4.65 and php 8.4. The install with composer was error free, too the horde-reconfigure and horde-db-migrate.
After restarting apache I get the logon screen and after logon I get following error:
A fatal error has occurred

Class "Horde_Crypt_Blowfish" not found

Details have been logged for the administrator.

I tried to install horde_crypt_Blowfish  with pear install horde/horde_crypt_blowfish, but this gives me following error:
horde/Horde_Crypt_Blowfish requires PHP (version >= 5.3.0, version <= 8.0.0alpha1, excluded versions: 8.0.0alpha1), installed version is 8.4.19.

How can I fix these problems or any more information I need to supply?

Thanks and Regards,
Horst Simon