A 13-week multi-center single-arm trial, preceded by a 2-week standard therapy phase, will be conducted to assess the safety of MODI, an insulin titration algorithm, in adults with type 1 diabetes (T1D) who use multiple daily insulin injections (MDI), or with type 2 diabetes (T2D) who use MDI, basal insulin only, or who are candidates to initiate basal insulin, in conjunction with continuous glucose monitoring (CGM).

Inclusion Criteria:

1. Clinical diagnosis, based on investigator assessment, of T1D or T2D of at least 6 months duration at time of informed consent

2. Insulin therapy as follows:

   1. If T1D, using MDI insulin therapy for at least 3 months prior to screening; willing to follow a mealtime insulin dosing approach during the study, using either (a) time-of-day-based dosing (breakfast, lunch, dinner) or (b) meal-size-based dosing (small, normal, large); and taking

      1 basal insulin injection per day for at least 1 week prior to screening

   2. If T2D, either:

   i. not using insulin in the 3 months prior to screening, but require initiation of a basal-only insulin regimen based on investigator assessment ii. using only basal insulin for at least 3 months prior to screening and taking 1 basal insulin injection per day for at least 1 week prior to screening iii. using MDI for at least 3 months prior to screening; willing to follow a mealtime insulin dosing approach during the study, using either

   (a) time-of-day-based dosing (breakfast, lunch, dinner) or (b) mealsize-based dosing (small, normal, large); and taking 1 basal insulin injection per day for at least 1 week prior to screening

3. Age at time of consent 18-80 years

4. HbA1c >7.5% and <12% as measured by point-of-care device or local lab at the time of screening

5. Using only injected insulin types that are specified in the MODI Instructions for Use materials

6. Stable doses of non-insulin glucose lowering medications over the 4 weeks preceding screening as determined by Investigator and no changes anticipated for the duration of the study, unless a dose reduction or discontinuation, as determined by Investigator, is indicated for safety reasons

7. Stable doses of weight loss medications that may have a meaningful effect on glycemic control over the 4 weeks preceding screening and no changes anticipated for the duration of the study, unless a dose reduction or discontinuation, as determined by Investigator, is indicated for safety reasons

8. Weight between 80 - 440 lb at the time of screening

9. Willing to use FSL 3 System according to manufacturer instructions and to avoid use of any other personal CGM system during the period of study participation

10. Willing to document insulin delivery, meals, and daily activities in the Diary mobile app

11. Has a smartphone compatible with study requirements: either iOS version 17.0 or higher, or Android version 10.0 or higher, and willing to install required apps and use them as instructed during the period of study participation, with internet connectivity for a data upload at least once per day.

12. Is deemed an appropriate candidate for automatic insulin guidance therapy per Investigator assessment

13. Investigator has confidence that the participant has the cognitive ability necessary for study participation, can successfully operate all study devices, and can adhere to the protocol

14. Has a sufficient understanding of written/spoken English for legally effective informed consent and successful use of the study mobile apps

15. If woman of childbearing potential, is willing and able to have pregnancy testing

Exclusion Criteria:

1. Use of an insulin pump within 3 months prior to informed consent
2. Use of mixed insulin or intermediate insulin (NPH) within the past 3 months prior to screening
3. Taking more than 128 units of daily basal insulin or more than 79 units in a single bolus insulin injection in the 7 days prior to screening
4. Any medical condition which in the opinion of the investigator, would put the participant at an unacceptable safety risk, such as untreated malignancy, unstable cardiac disease, unstable or end-stage renal disease, and/or eating disorders (i.e. anorexia/bulimia)
5. Current or known history of coronary artery disease that is not stable with medical management, including unstable angina, or angina that prevents moderate exercise despite medical management, or a history of myocardial infarction, percutaneous coronary intervention, or coronary artery bypass grafting within the 12 months prior to screening
6. Any planned surgery during the study which could be considered major in the judgment of the investigator
7. History of more than 1 severe hypoglycemic event in the 6 months prior to screening
8. History of diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic syndrome (HHS) in the 6 months prior to screening
9. Blood disorder or dyscrasia within 3 months prior to screening which in the investigator's opinion could interfere with determination of HbA1c
10. Any condition or intervention that may affect red blood cell turnover, in the 3 months prior to the study and during the study, such as blood transfusion or donation
11. Has taken oral or injectable corticosteroids within 2 weeks prior to screening or plans to take oral or injectable corticosteroids during the study
12. Unable to follow clinical protocol for the duration of the study or is otherwise deemed unacceptable to participate in the study per the Investigator's clinical judgment
13. Is an employee of DreaMed Diabetes, is a study Investigator or a member of the Investigator's study team, or is immediate family member (spouse, biological or legal guardian, child, sibling, parent) of any of the aforementioned
14. Participation in another clinical study using an investigational drug or device in the 90 days prior to screening or intends to participate during the study period
15. Pregnant or lactating, planning to become pregnant during the study, or is a woman of childbearing potential and not on acceptable form of birth control (acceptable includes abstinence, condoms, oral/injectable contraceptives, IUD, or implant); childbearing potential means that menstruation has started, and the participant is not surgically sterile or greater than 12 months postmenopausal)
16. Unable to tolerate adhesive tape or has any unresolved skin condition that could impact the CGM sensor