What is the DUCA and what is the difference between DUCA-D, DUCA-F and DUCA-T?

Since 1 April 2019 the DUCA (Single Central American Declaration) has replaced the FAUCA, the DUT and the DUA-GT, under Resolution 409-2018 of COMIECO. DUCA-D: imports from outside Central America and other national regimes; DUCA-F: goods originating in intra-regional trade (successor to the FAUCA); DUCA-T: international overland customs transit (successor to the DUT). Trade between Guatemala, Honduras and El Salvador under the customs union uses the FYDUCA, not the DUCA. SEADEX Web, run by VUPE/AGEXPORT, issues DUCA-F and DUCA-D 24/7.