Piotr Przybylski ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *commented* on HHH-16671 ( https://hibernate.atlassian.net/browse/HHH-16671?atlOrigin=eyJpIjoiNzY4Nm... ) Re: Unable to query key attribute that uses AttributeConverter ( https://hibernate.atlassian.net/browse/HHH-16671?atlOrigin=eyJpIjoiNzY4Nm... ) Thanks for the explanation. I may have been too hasty in reusing that other issue’s tests, sorry for that. What about the new @Type annotation? Is this supposed to work: @Id @Column(name = "year_month_key" ) @Type(YearMonthDateType.class) private YearMonth yearMonthKey; @Column(name = "year_month_value" ) @Type(YearMonthDateType.class) private YearMonth yearMonthValue; and then: entityManager.createQuery( "SELECT MAX(de.yearMonthKey) FROM DemoEntity de" ); entityManager.createQuery( "SELECT MAX(de.yearMonthValue) FROM DemoEntity de" ); ? I’m trying to migrate code that in 5.6 used: @TypeDefs({ @TypeDef(name = "yearmonth-date" , typeClass = YearMonthDateType.class, defaultForType = YearMonth.class), }) package pl.coretech.cdn.domain; import io.hypersistence.utils.hibernate.type.basic.YearMonthDateType; import org.hibernate.annotations.TypeDef; import org.hibernate.annotations.TypeDefs; import java.time.YearMonth; When I’m trying this on @Id column I get Could not create JdbcLiteralFormatter, UserType class [io.hypersistence.utils.hibernate.type.basic.YearMonthDateType] did not implement org.hibernate.usertype.EnhancedUserType , so this may be a Hypersistence issue, but what about that @Type on regular column? I’m attaching a test case with code above in case you want to look into this: test-case-2.zip ( https://hibernate.atlassian.net/rest/api/3/attachment/content/50421 ) ( https://hibernate.atlassian.net/browse/HHH-16671#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16671#add-comment?atlOrigin=ey... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100225- sha1:da60ad2 )