Use mustBeConnected annotation (introduced in Modelica 3.6)

[HansOlsson]

for all conditional support connectors in Rotational and Translational; based on decision in #4175

See "Modelica 3.6 - Changes, Benefits and Implementation" by Hans Olsson, from Modelica Conference 2023, https://www.conftool.com/modelica2023/index.php?page=browseSessions&form_session=34

In Dymola 2024x the library should still work after the change, but if you introduce an unconnected support connector in a model it will fail, e.g.:

model First "First example: simple drive train"
  extends Modelica.Icons.Example;
  parameter Modelica.Units.SI.Torque amplitude=10 "Amplitude of driving torque";
  parameter Modelica.Units.SI.Frequency f=5 "Frequency of driving torque";
  parameter Modelica.Units.SI.Inertia Jmotor(min=0)=0.1 "Motor inertia";
  parameter Modelica.Units.SI.Inertia Jload(min=0)=2 "Load inertia";
  parameter Real ratio=10 "Gear ratio";
  parameter Real damping=10 "Damping in bearing of gear";

  Modelica.Mechanics.Rotational.Components.Fixed fixed
    annotation (Placement(transformation(extent={{38,-48},{54,-32}})));
  Modelica.Mechanics.Rotational.Sources.Torque torque(useSupport=true)
    annotation (Placement(transformation(extent={{-68,-8},{-52,8}})));
  Modelica.Mechanics.Rotational.Components.Inertia inertia1(J=Jmotor)
    annotation (Placement(transformation(extent={{-38,-8},{-22,8}})));
  Modelica.Mechanics.Rotational.Components.IdealGear idealGear(ratio=ratio,
      useSupport=true)
    annotation (Placement(transformation(extent={{-8,-8},{8,8}})));
  Modelica.Mechanics.Rotational.Components.Inertia inertia2(
    J=2,
    phi(fixed=true, start=0),
    w(fixed=true, start=0))
    annotation (Placement(transformation(extent={{22,-8},{38,8}})));
  Modelica.Mechanics.Rotational.Components.Spring spring(c=1.e4, phi_rel(fixed=true))
    annotation (Placement(transformation(extent={{52,-8},{68,8}})));
  Modelica.Mechanics.Rotational.Components.Inertia inertia3(J=Jload, w(fixed=true,
        start=0))
    annotation (Placement(transformation(extent={{82,-8},{98,8}})));
  Modelica.Mechanics.Rotational.Components.Damper damper(d=damping) annotation 
    (Placement(transformation(
        origin={46,-22},
        extent={{-8,-8},{8,8}},
        rotation=270)));
  Modelica.Blocks.Sources.Sine sine(amplitude=amplitude, f=f)
    annotation (Placement(transformation(extent={{-98,-8},{-82,8}})));
equation 
  connect(inertia1.flange_b, idealGear.flange_a)
    annotation (Line(points={{-22,0},{-8,0}}));
  connect(idealGear.flange_b, inertia2.flange_a)
    annotation (Line(points={{8,0},{22,0}}));
  connect(inertia2.flange_b, spring.flange_a)
    annotation (Line(points={{38,0},{52,0}}));
  connect(spring.flange_b, inertia3.flange_a)
    annotation (Line(points={{68,0},{82,0}}));
  connect(damper.flange_a, inertia2.flange_b)
    annotation (Line(points={{46,-14},{46,0},{38,0}}));
  connect(damper.flange_b, fixed.flange)
    annotation (Line(points={{46,-30},{46,-40}}));
  connect(sine.y, torque.tau)
    annotation (Line(points={{-81.2,0},{-69.6,0}}, color={0,0,127}));
  connect(torque.support, fixed.flange)
    annotation (Line(points={{-60,-8},{-60,-40},{46,-40}}));
  connect(torque.flange, inertia1.flange_a) annotation (Line(
      points={{-52,0},{-38,0}}));
  annotation (
    experiment(StopTime=1.0, Interval=0.001),
    uses(Modelica(version="4.0.0")));
end First;

[tobolar]

Looks good!