ERROR: unrecognized parameter "autovacuum_analyze_scale_factor"

Hey,
I have a very big toasted table in my db(9.2.5). Autovacuum doesnt gather
statistics on it because the analyze_scale/threshold are default and as a
result autoanalyze is never run and the statistics are wrong :

select * from pg_stat_all_Tables where relname='pg_toast_13488395';
-[ RECORD 1 ]-----+------------------------------
relid | 13388396
schemaname | pg_toast
relname | pg_toast_13488395
seq_scan | 42
seq_tup_read | 71163925
idx_scan | 5374497
idx_tup_fetch | 2530272449
n_tup_ins | 1253680014
n_tup_upd | 0
n_tup_del | 1253658363
n_tup_hot_upd | 0
n_live_tup | 49425717 *wrong*
n_dead_tup | 7822920 *wrong*
last_vacuum |
last_autovacuum | 2019-02-12 20:54:44.247083-05
last_analyze |
*last_autoanalyze |*
vacuum_count | 0
autovacuum_count | 3747
analyze_count | 0
autoanalyze_count | 0

When I try to set the both the scale_factor / threshold I'm getting the
next error :
alter table orig_table set (toast.autovacuum_analyze_scale_factor=0);
ERROR: unrecognized parameter "autovacuum_analyze_scale_factor"

Any idea why ? I didn't find in the release documentations a note for a
similar bug.