Error in estimation1

I get the following error when running the model?
Warning: Identifier ‘delta’ in the evaluated statement does not refer to the external function. In a future release, using an identifier
different to how it is used in the file will not be supported.

In bank_steadystate (line 20)
In evaluate_steady_state_file (line 49)
In evaluate_steady_state (line 254)
In dynare_estimation_init (line 588)
In dynare_estimation_1 (line 110)
In dynare_estimation (line 118)
In bank.driver (line 419)
In dynare (line 281)

Check for incorrect argument data type or missing argument in call to function ‘isShapeOnXY’.

Error in - (line 758)
if ~isShapeOnXY(poly1)||~isShapeOnXY(poly2)

Error in bank_steadystate (line 37)

Error in evaluate_steady_state_file (line 49)
[ys,params1,check] = h_steadystate(ys_init, exo_ss,M,options);

Error in evaluate_steady_state (line 254)
[ys,params,info] = evaluate_steady_state_file(ys_init,exo_ss,M, options,steadystate_check_flag);

Error in dynare_estimation_init (line 588)
[oo_.steady_state, params,info] = evaluate_steady_state(oo_.steady_state,M,options_,oo_,steadystate_check_flag);

Error in dynare_estimation_1 (line 110)
dynare_estimation_init(var_list_, dname, , M_, options_, oo_, estim_params_, bayestopt_);

Error in dynare_estimation (line 118)

Error in bank.driver (line 419)

Error in dynare (line 281)
evalin(‘base’,[fname ‘.driver’]);

Can this error be related to the MATLAB version?
Because this code is executed in MATLAB 2018, but in MATLAB 2021, I get the above error:
bank.mod (5.3 KB)
bank_steadystate.m (2.0 KB)
data_bank.m (2.8 KB)

You seem to having a naming conflict. There must be function delta.m in your path that Matlab tries to call instead of the variable.