diff --git a/l10n_br_base/models/party_mixin.py b/l10n_br_base/models/party_mixin.py
index 04557895aef8..6911f4eb3590 100644
--- a/l10n_br_base/models/party_mixin.py
+++ b/l10n_br_base/models/party_mixin.py
@@ -43,12 +43,15 @@ class PartyMixin(models.AbstractModel):
         inverse_name="partner_id",
     )
 
-    inscr_mun = fields.Char(
+    l10n_br_im_code = fields.Char(
         string="Municipal Tax Number",
         size=18,
         unaccent=False,
     )
 
+    # backward compat with v14:
+    inscr_mun = fields.Char(related="l10n_br_im_code", readonly=False)
+
     suframa = fields.Char(
         size=18,
         unaccent=False,
diff --git a/l10n_br_base/models/res_company.py b/l10n_br_base/models/res_company.py
index 59668ba75cb6..2a301ecff50f 100644
--- a/l10n_br_base/models/res_company.py
+++ b/l10n_br_base/models/res_company.py
@@ -20,7 +20,7 @@ def _get_company_address_field_names(self):
             "legal_name",
             "cnpj_cpf",
             "inscr_est",
-            "inscr_mun",
+            "l10n_br_im_code",
             "district",
             "city_id",
             "suframa",
@@ -72,10 +72,10 @@ def _inverse_state_tax_number_ids(self):
                 state_tax_number_ids |= ies
             company.partner_id.state_tax_number_ids = state_tax_number_ids
 
-    def _inverse_inscr_mun(self):
+    def _inverse_l10n_br_im_code(self):
         """Write the l10n_br specific functional fields."""
         for company in self:
-            company.partner_id.inscr_mun = company.inscr_mun
+            company.partner_id.l10n_br_im_code = company.l10n_br_im_code
 
     def _inverse_city_id(self):
         """Write the l10n_br specific functional fields."""
@@ -133,9 +133,9 @@ def _inverse_suframa(self):
         inverse="_inverse_state_tax_number_ids",
     )
 
-    inscr_mun = fields.Char(
+    l10n_br_im_code = fields.Char(
         compute="_compute_address",
-        inverse="_inverse_inscr_mun",
+        inverse="_inverse_l10n_br_im_code",
     )
 
     suframa = fields.Char(
diff --git a/l10n_br_base/models/res_partner.py b/l10n_br_base/models/res_partner.py
index 48c108830577..2eb8a57202b4 100644
--- a/l10n_br_base/models/res_partner.py
+++ b/l10n_br_base/models/res_partner.py
@@ -203,7 +203,7 @@ def _compute_show_l10n_br(self):
     def create_company(self):
         self.ensure_one()
         inscr_est = self.inscr_est
-        inscr_mun = self.inscr_mun
+        inscr_mun = self.l10n_br_im_code
         res = super().create_company()
         if res:
             parent = self.parent_id
diff --git a/l10n_br_base/views/res_company_view.xml b/l10n_br_base/views/res_company_view.xml
index 32a13a1a0b9c..9e43c1b3f13c 100644
--- a/l10n_br_base/views/res_company_view.xml
+++ b/l10n_br_base/views/res_company_view.xml
@@ -30,7 +30,7 @@
                     attrs="{'invisible': [('country_id', '!=', %(base.br)d)]}"
                 />
                 <field
-                    name="inscr_mun"
+                    name="l10n_br_im_code"
                     placeholder="Municipal Tax Number..."
                     attrs="{'invisible': [('country_id', '!=', %(base.br)d)]}"
                 />
diff --git a/l10n_br_base/views/res_partner_view.xml b/l10n_br_base/views/res_partner_view.xml
index b2e4f04a49a7..15237ec83ac3 100644
--- a/l10n_br_base/views/res_partner_view.xml
+++ b/l10n_br_base/views/res_partner_view.xml
@@ -112,7 +112,7 @@
                         <group string="Fiscal Infos" name="fiscal_numbers">
                             <field name="cei_code" />
                             <field
-                                name="inscr_mun"
+                                name="l10n_br_im_code"
                                 attrs="{'invisible': [('is_company','!=', True)]}"
                             />
                             <field