Version 5.3 cannot read data from Firebird 2.5, therefore odb files embedding firebird and created up to version LibreOffice 5.2 (incompatibility between firebird 2.5 used until LO 5.2 and Firebird 3.0 used by LO 5.3

ODB files embedding Firebird 2.5 (up to JO 5.2) not compatible with LO 5.3 (embedding Firebird 3.0)

I'm trying the file conversion procedure (while waiting for compatibility) but I'm having a problem.

The Gbak that I wrote seems to work, but after replacing firebird.fdb file by firebird.fbk file (created by gbak 2.5) in the odb database, LO 5.3 can not open the database odb because "file corrupted".

I have done the manipulations of the odb file with 7-Zip. 

Gbak (Win7/x86): 

"C:\Program Files\Firebird\Firebird_2_5\bin\gbak.exe"  -verbose -y %USERPROFILE%\Desktop\gbak.log -user SYSDBA -password masterkey -convert  localhost:%USERPROFILE%\Desktop\firebird.fdb %USERPROFILE%\Desktop\firebird.fbk 

Gbak execution report :

gbak:readied database localhost:C:\Users\Bernard\Desktop\firebird.fdb for backup
gbak:creating file C:\Users\Bernard\Desktop\firebird.fbk
gbak:starting transaction
gbak:database localhost:C:\Users\Bernard\Desktop\firebird.fdb has a page size of 4096 bytes.
gbak:writing domains
gbak:    writing domain RDB$1
gbak:    writing domain RDB$3
gbak:writing shadow files
gbak:writing character sets
gbak:writing collations
gbak:writing functions
gbak:writing tables
gbak:    writing table Table1
gbak:         writing column lib
gbak:         writing column ID
gbak:writing types
gbak:writing filters
gbak:writing id generators
gbak:writing stored procedures
gbak:writing exceptions
gbak:    writing index RDB$PRIMARY1
gbak:    writing data for table Table1
gbak:2 records written
gbak:writing triggers
gbak:writing trigger messages
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user PUBLIC
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user PUBLIC
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user PUBLIC
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:    writing privilege for user 
gbak:writing table constraints
gbak:writing constraint INTEG_1
gbak:writing constraint INTEG_2
gbak:writing referential constraints
gbak:writing check constraints
gbak:writing SQL roles
gbak:writing names mapping
gbak:closing file, committing, and finishing. 2048 bytes written