The maximum length of Text variables depends on the Unicode mode of the database. In compatibility mode it is still 32000 characters (as with previous versions of 4D). In Unicode mode a Text variable can have up to 2GB of data.
Note that the "Unicode mode" setting only exists in databases that have been upgraded to 4D v11 SQL. It does not exist in databases created in 4D v11 SQL. New databases are always in Unicode mode.