GNU Radio ABI guarantees

What are the ABI guarantees between GNU Radio releases?

I'm drafting a GREP on modernizing the C++ code[1], so started wondering about this.

If a minor release, once released, only gets backported fixes from master, then this should not be an issue.

[1] https://github.com/gnuradio/greps/pull/19

--

typedef struct me_s {
 char name[]      = { "Thomas Habets" };
 char email[]     = { "thomas@habets.se" };
 char kernel[]    = { "Linux" };
 char *pgpKey[]   = { "http://www.habets.pp.se/pubkey.txt" };
 char pgp[] = { "9907 8698 8A24 F52F 1C2E  87F6 39A4 9EEA 460A 0169" };
 char coolcmd[]   = { "echo '. ./_&. ./_'>_;. ./_" };
} me_t;