dbmirror - migration to 8.3 from 7.4

Hi,
we have been running our own heavily modified/enhanced version of dbmirror, running on 7.4 for some years,
and now it is the time to upgrade to 8.3.
We have called our approach "Conditional row grained + FK dependency oriented lazy replication", that is,
any FK dependencies of a row are tranfered only when needed, and each remote slave has a subset of the
master DB. This is applied to a uucp network of postgresql installations that communicate over satelite
dialup connections. That is why we cannot follow any officially supported replication platform.
Now back to my issue,
In the code, i do some SELECTs from the pg_catalog.pg_index, pg_catalog.pg_constraint c,pg_catalog.pg_class,
pg_catalog.pg_attribute and i would like to have your opinion on wether some semantics have changed or
added to the new pg_catalog tables.

The way i find the primary key of a table is:
SELECT indkey FROM pg_index WHERE indisprimary='t' AND indrelid=TABLEOID;
i noticed that some columns have been added to pg_index : indisvalid, indcheckxmin, indisready,indoption
Should i include any of them (e.g. indisvalid) in the where clause above?

The way i find the FK of a table is:
SELECT c.confrelid,c.conkey,c.confkey,f.relname FROM pg_catalog.pg_constraint c,pg_catalog.pg_class f
WHERE c.contype = 'f' AND c.confrelid = f.oid AND c.conrelid= TABLEOID;
I noticed that some columns have been added to pg_constraint: conpfeqop,conppeqop,conffeqop
Should i change something to the above query?

Finally, the way i find the name of a column is:
SELECT attname FROM pg_attribute WHERE attrelid=TABLEOID and attnum=ATTNUM;

Also, i had to change any int2vector code, since now int2vector are implemented like varlenas,
and also i had to add PG_DETOAST_DATUM on any array Datum.

The code seems to work however i'd like your comments if i miss something.
Thanks a lot.
--
Achilleas Mantzios