Confluence upgrade from 7.15 to 7.19 or 7.20 fails

[mislekfti]

We have tried it many different ways, but the upgrade of Confluence from 7.15 to 7.19 or 7.20 fails due to missing table.

caused by: java.lang.RuntimeException: Could not read fields for table AO_ED669C_IDP_CONFIG
    at net.java.ao.schema.helper.DatabaseMetaDataReaderImpl.getFields(DatabaseMetaDataReaderImpl.java:141)

caused by: java.sql.SQLSyntaxErrorException: Table 'confluence.AO_ED669C_IDP_CONFIG' doesn't exist
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)

[Nic Brough -Adaptavist-]

You have not told us how you are trying to upgrade, but the tables you have mentioned are from an SSO app, so my best guess is that you don't have that installed properly.